Device and method for transmitting or receiving data in wireless power transmission system

ABSTRACT

The present invention relates to a device and a method for transmitting or receiving data in a wireless power transmission system. The present specification discloses a wireless power reception device comprising: a power pickup unit configured to receive, from a wireless power transmission device, wireless power generated on the basis of magnetic coupling in a power transmission phase; and a communication/control unit configured to receive, from the wireless power transmission device, information on a first buffer size indicating the size of a first buffer for receiving a data transmission stream. As the buffer size for exchanging the data transmission stream between the wireless power transmission device and reception device becomes clear, wireless power transmission and communication can proceed smoothly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application in a continuation of U.S. application Ser. No.16/992,862, filed on Aug. 13, 2020, which is a continuation pursuant to35 U.S.C. § 119(e) of International Application PCT/KR2019/007741, withan international filing date of Jun. 26, 2019, which claims the benefitof Korean Patent Application No. 10-2018-0074861, filed on Jun. 28,2018, the contents of which are hereby incorporated by reference hereinin their entirety.

TECHNICAL FIELD

The present disclosure relates to a wireless power transmission systemand, more particularly, to a method and apparatus for transmitting orreceiving data.

BACKGROUND ART

A contactless wireless charging method is an energy transfer method forelectromagnetically transferring energy without using a wire in a methodfor sending energy through an existing wire so that the energy is usedas power for an electronic device. The contactless wireless transmissionmethod includes an electromagnetic induction method and a resonantmethod. In the electromagnetic induction method, a power transmissionunit generates a magnetic field through a power transmission coil (i.e.,a primary coil), and a power reception coil (i.e., a secondary coil) isplaced at the location where an electric current may be induced so thatpower is transferred. In the resonant method, energy is transmittedusing a resonant phenomenon between the transmission coil and thereception coil. In this case, a system is configured so that the primarycoil and the secondary coil have the same resonant frequency, andresonant mode energy coupling between the transmission and receptioncoils is used.

A wireless power transmission system may include a message exchangefunction of an application layer for supporting an extension to variousapplication fields. Based on the function, authentication relatedinformation or other information on an application level of a device maybe transmitted and received between a wireless power transmission deviceand a wireless power reception device. For the exchange of higher layermessages between a wireless power transmission device and a wirelesspower reception device, a separate hierarchical architecture for datatransmission is required, and an efficient managing and operating methodis required for the hierarchical architecture.

DISCLOSURE Technical Problem

An aspect of the present disclosure is to provide a wireless powertransmission device or a wireless power reception device fortransmitting data in a higher layer or an application layer level.

Another aspect of the present disclosure is to provide a wireless powertransmission device or a wireless power reception device for receivingdata in a higher layer or an application layer level.

Another aspect of the present disclosure is to provide a method for awireless power transmission device or a wireless power reception deviceto transmit data in a higher layer or an application layer level.

Another aspect of the present disclosure is to provide a method for awireless power transmission device or a wireless power reception deviceto receive data in a higher layer or an application layer level.

Technical Solution

According to an aspect of the present disclosure, it is provided awireless power reception device including a power pickup unit configuredto receive a wireless power generated based on magnetic coupling from awireless power transmission device in a power transfer phase, and acommunication/control unit configured to receive information for a firstbuffer size informing a size of a first buffer for the wireless powertransmission device to receive a data transfer stream from the wirelesspower reception device.

In an aspect, the information for the first buffer size may be receivedby being included in a capability packet of the wireless powertransmission device.

In another aspect, the first buffer size may be defined as amultiplication of a minimum buffer size k and 2^(n), and the informationfor the first buffer size may be the n.

In still another aspect, the communication/control unit may receive theinformation for the first buffer size in a negotiation phase.

In still another aspect, the communication/control unit may transmitinformation for a second buffer size informing a size of a second bufferfor the wireless power transmission device to receive a data transferstream to the wireless power transmission device.

In still another aspect, the information for the second buffer size maybe transmitted with being included in a configuration packet of thewireless power reception device.

In still another aspect, the second buffer size may be defined as amultiplication of a minimum buffer size k′ and 2^(m), and theinformation for the second buffer size may be the m.

According to an aspect of the present disclosure, it is provided awireless power transmission device including a power conversion unitconfigured to transmit a wireless power generated based on magneticcoupling to a wireless power reception device in a power transfer phase;and a communication/control unit configured to transmit information fora first buffer size informing a size of a first buffer for receiving adata transfer stream from the wireless power reception device to thewireless power reception device.

In an aspect, the information for the first buffer size may betransmitted by being included in a capability packet of the wirelesspower transmission device.

In another aspect, the first buffer size may be defined as amultiplication of a minimum buffer size k and 2^(n), and the informationfor the first buffer size may be the n.

In still another aspect, the communication/control unit may transmit theinformation for the first buffer size in a negotiation phase.

In still another aspect, the communication/control unit may receiveinformation for a second buffer size informing a size of a second bufferfor the wireless power reception device to receive a data transferstream from the wireless power reception device.

In still another aspect, the information for the second buffer size maybe received with being included in a configuration packet of thewireless power reception device.

In still another aspect, the second buffer size may be defined as amultiplication of a minimum buffer size k′ and 2^(m), and theinformation for the second buffer size may be the m.

Advantageous Effects

A buffer size for exchanging a data transport stream becomeswell-defined between a wireless power transmission device and a wirelesspower reception device, and a wireless power transmission andcommunication can be smoothly processed.

DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of a wireless power system (10) according toan exemplary embodiment of the present disclosure.

FIG. 2 is a block diagram of a wireless power system (10) according toanother exemplary embodiment of the present disclosure.

FIG. 3A shows an exemplary embodiment of diverse electronic devicesadopting a wireless power transfer system.

FIG. 3B shows an example of a WPC NDEF in a wireless power transfersystem.

FIG. 4A is a block diagram of a wireless power transfer system accordingto another exemplary embodiment of the present disclosure.

FIG. 4B is a diagram illustrating an example of a Bluetoothcommunication architecture to which an embodiment according to thepresent disclosure may be applied.

FIG. 4C is a block diagram illustrating a wireless power transfer systemusing BLE communication according to an example.

FIG. 4D is a block diagram illustrating a wireless power transfer systemusing BLE communication according to another example.

FIG. 5 is a state transition diagram for describing a wireless powertransfer procedure.

FIG. 6 shows a power control method according to an exemplary embodimentof the present disclosure.

FIG. 7 is a block diagram of a wireless power transmitter according toanother exemplary embodiment of the present disclosure.

FIG. 8 shows a wireless power receiver according to another exemplaryembodiment of the present disclosure.

FIG. 9 shows a communication frame structure according to an exemplaryembodiment of the present disclosure.

FIG. 10 is a structure of a sync pattern according to an exemplaryembodiment of the present disclosure.

FIG. 11 shows operation statuses of a wireless power transmitter and awireless power receiver in a shared mode according to an exemplaryembodiment of the present disclosure.

FIG. 12 shows an application-level data stream between a wireless powertransmitter and a wireless power receiver according to an example.

FIG. 13 illustrates a hierarchical architecture for transmitting a datastream between a wireless power transmission device and a wireless powerreception device.

FIG. 14 illustrates a capability packet structure of a wireless powertransmission device including a buffer size field according to anembodiment.

FIG. 15 illustrates a capability packet structure of a wireless powertransmission device including a buffer size field according to anotherembodiment.

FIG. 16 illustrates a configuration packet structure of a wireless powerreception device including a buffer size field according to anembodiment.

FIG. 17 is a flowchart illustrating a method for negotiating a buffersize according to an embodiment.

FIG. 18 illustrates a structure of a response packet of a wireless powerreception device according to an example.

FIG. 19 illustrates a method for processing ADT data packet according toan example.

MODE FOR DISCLOSURE

The term “wireless power”, which will hereinafter be used in thisspecification, will be used to refer to an arbitrary form of energy thatis related to an electric field, a magnetic field, and anelectromagnetic field, which is transferred (or transmitted) from awireless power transmitter to a wireless power receiver without usingany physical electromagnetic conductors. The wireless power may also bereferred to as a wireless power signal, and this may refer to anoscillating magnetic flux that is enclosed by a primary coil and asecondary coil. For example, power conversion for wirelessly chargingdevices including mobile phones, cordless phones, iPods, MP3 players,headsets, and so on, within the system will be described in thisspecification. Generally, the basic principle of the wireless powertransfer technique includes, for example, all of a method oftransferring power by using magnetic coupling, a method of transferringpower by using radio frequency (RF), a method of transferring power byusing microwaves, and a method of transferring power by using ultrasound(or ultrasonic waves).

FIG. 1 is a block diagram of a wireless power system (10) according toan exemplary embodiment of the present disclosure.

Referring to FIG. 1, the wireless power system (10) include a wirelesspower transmitter (100) and a wireless power receiver (200).

The wireless power transmitter (100) is supplied with power from anexternal power source (S) and generates a magnetic field. The wirelesspower receiver (200) generates electric currents by using the generatedmagnetic field, thereby being capable of wirelessly receiving power.

Additionally, in the wireless power system (10), the wireless powertransmitter (100) and the wireless power receiver (200) may transceive(transmit and/or receive) diverse information that is required for thewireless power transfer. Herein, communication between the wirelesspower transmitter (100) and the wireless power receiver (200) may beperformed (or established) in accordance with any one of an in-bandcommunication, which uses a magnetic field that is used for the wirelesspower transfer (or transmission), and an out-band communication, whichuses a separate communication carrier. Out-band communication may alsobe referred to as out-of-band communication. Hereinafter, out-bandcommunication will be largely described. Examples of out-bandcommunication may include NFC, Bluetooth, Bluetooth low energy (BLE),and the like.

Herein, the wireless power transmitter (100) may be provided as a fixedtype or a mobile (or portable) type. Examples of the fixed transmittertype may include an embedded type, which is embedded in in-door ceilingsor wall surfaces or embedded in furniture, such as tables, an implantedtype, which is installed in out-door parking lots, bus stops, subwaystations, and so on, or being installed in means of transportation, suchas vehicles or trains. The mobile (or portable) type wireless powertransmitter (100) may be implemented as a part of another device, suchas a mobile device having a portable size or weight or a cover of alaptop computer, and so on.

Additionally, the wireless power receiver (200) should be interpreted asa comprehensive concept including diverse home appliances and devicesthat are operated by being wirelessly supplied with power instead ofdiverse electronic devices being equipped with a battery and a powercable. Typical examples of the wireless power receiver (200) may includeportable terminals, cellular phones, smartphones, personal digitalassistants (PDAs), portable media players (PDPs), Wibro terminals,tablet PCs, phablet, laptop computers, digital cameras, navigationterminals, television, electronic vehicles (EVs), and so on.

In the wireless power system (10), one wireless power receiver (200) ora plurality of wireless power receivers may exist. Although it is shownin FIG. 1 that the wireless power transmitter (100) and the wirelesspower receiver (200) send and receive power to and from one another in aone-to-one correspondence (or relationship), as shown in FIG. 2, it isalso possible for one wireless power transmitter (100) to simultaneouslytransfer power to multiple wireless power receivers (200-1, 200-2, . . ., 200-M). Most particularly, in case the wireless power transfer (ortransmission) is performed by using a magnetic resonance method, onewireless power transmitter (100) may transfer power to multiple wirelesspower receivers (200-1, 200-2, . . . , 200-M) by using a synchronizedtransport (or transfer) method or a time-division transport (ortransfer) method.

Additionally, although it is shown in FIG. 1 that the wireless powertransmitter (100) directly transfers (or transmits) power to thewireless power receiver (200), the wireless power system (10) may alsobe equipped with a separate wireless power transceiver, such as a relayor repeater, for increasing a wireless power transport distance betweenthe wireless power transmitter (100) and the wireless power receiver(200). In this case, power is delivered to the wireless powertransceiver from the wireless power transmitter (100), and, then, thewireless power transceiver may transfer the received power to thewireless power receiver (200).

Hereinafter, the terms wireless power receiver, power receiver, andreceiver, which are mentioned in this specification, will refer to thewireless power receiver (200). Also, the terms wireless powertransmitter, power transmitter, and transmitter, which are mentioned inthis specification, will refer to the wireless power transmitter (100).

FIG. 3a shows an exemplary embodiment of diverse electronic devicesadopting a wireless power transfer system.

As shown in FIG. 3a , the electronic devices included in the wirelesspower transfer system are sorted in accordance with the amount oftransmitted power and the amount of received power. Referring to FIG. 3,wearable devices, such as smart watches, smart glasses, head mounteddisplays (HMDs), smart rings, and so on, and mobile electronic devices(or portable electronic devices), such as earphones, remote controllers,smartphones, PDAs, tablet PCs, and so on, may adopt a low-power(approximately 5 W or less or approximately 20 W or less) wirelesscharging method.

Small-sized/Mid-sized electronic devices, such as laptop computers,robot vacuum cleaners, TV receivers, audio devices, vacuum cleaners,monitors, and so on, may adopt a mid-power (approximately 50 W or lessor approximately 200 W or less) wireless charging method. Kitchenappliances, such as mixers, microwave ovens, electric rice cookers, andso on, and personal transportation devices (or other electric devices ormeans of transportation), such as powered wheelchairs, powered kickscooters, powered bicycles, electric cars, and so on may adopt ahigh-power (approximately 2 kW or less or approximately 22 kW or less)wireless charging method.

The electric devices or means of transportation, which are describedabove (or shown in FIG. 1) may each include a wireless power receiver,which will hereinafter be described in detail. Therefore, theabove-described electric devices or means of transportation may becharged (or re-charged) by wirelessly receiving power from a wirelesspower transmitter.

Hereinafter, although the present disclosure will be described based ona mobile device adopting the wireless power charging method, this ismerely exemplary. And, therefore, it shall be understood that thewireless charging method according to the present disclosure may beapplied to diverse electronic devices.

A standard for the wireless power transfer (or transmission) includes awireless power consortium (WPC), an air fuel alliance (AFA), and a powermatters alliance (PMA).

The WPC standard defines a baseline power profile (BPP) and an extendedpower profile (EPP). The BPP is related to a wireless power transmitterand a wireless power receiver supporting a power transfer of SW, and theEPP is related to a wireless power transmitter and a wireless powerreceiver supporting the transfer of a power range greater than SW andless than 30 W.

Diverse wireless power transmitters and wireless power receivers eachusing a different power level may be covered by each standard and may besorted by different power classes or categories.

For example, the WPC may categorize (or sort) the wireless powertransmitters and the wireless power receivers as PC-1, PC0, PC1, andPC2, and the WPC may provide a standard document (or specification) foreach power class (PC). The PC-1 standard relates to wireless powertransmitters and receivers providing a guaranteed power of less than 5W. The application of PC-1 includes wearable devices, such as smartwatches.

The PC0 standard relates to wireless power transmitters and receiversproviding a guaranteed power of 5 W. The PC0 standard includes an EPPhaving a guaranteed power ranges that extends to 30 W. Although in-band(IB) communication corresponds to a mandatory communication protocol ofPC0, out-of-band (OB) communication that is used as an optional backupchannel may also be used for PC0. The wireless power receiver may beidentified by setting up an OB flag, which indicates whether or not theOB is supported, within a configuration packet. A wireless powertransmitter supporting the OB may enter an OB handover phase bytransmitting a bit-pattern for an OB handover as a response to theconfiguration packet. The response to the configuration packet maycorrespond to an NAK, an ND, or an 8-bit pattern that is newly defined.The application of the PC0 includes smartphones.

The PC1 standard relates to wireless power transmitters and receiversproviding a guaranteed power ranging from 30 W to 150 W. OB correspondsto a mandatory communication channel for PC1, and IB is used forinitialization and link establishment to OB. The wireless powertransmitter may enter an OB handover phase by transmitting a bit-patternfor an OB handover as a response to the configuration packet. Theapplication of the PC1 includes laptop computers or power tools.

The PC2 standard relates to wireless power transmitters and receiversproviding a guaranteed power ranging from 200 W to 2 kW, and itsapplication includes kitchen appliances.

As described above, the PCs may be differentiated in accordance with therespective power levels. And, information on whether or not thecompatibility between the same PCs is supported may be optional ormandatory. Herein, the compatibility between the same PCs indicates thatpower transfer/reception between the same PCs is possible. For example,in case a wireless power transmitter corresponding to PC x is capable ofperforming charging of a wireless power receiver having the same PC x,it may be understood that compatibility is maintained between the samePCs. Similarly, compatibility between different PCs may also besupported. Herein, the compatibility between different PCs indicatesthat power transfer/reception between different PCs is also possible.For example, in case a wireless power transmitter corresponding to PC xis capable of performing charging of a wireless power receiver having PCy, it may be understood that compatibility is maintained between thedifferent PCs.

The support of compatibility between PCs corresponds to an extremelyimportant issue in the aspect of user experience and establishment ofinfrastructure. Herein, however, diverse problems, which will bedescribed below, exist in maintaining the compatibility between PCs.

In case of the compatibility between the same PCs, for example, in caseof a wireless power receiver using a lap-top charging method, whereinstable charging is possible only when power is continuously transferred,even if its respective wireless power transmitter has the same PC, itmay be difficult for the corresponding wireless power receiver to stablyreceive power from a wireless power transmitter of the power toolmethod, which transfers power non-continuously. Additionally, in case ofthe compatibility between different PCs, for example, in case a wirelesspower transmitter having a minimum guaranteed power of 200 W transferspower to a wireless power receiver having a maximum guaranteed power of5 W, the corresponding wireless power receiver may be damaged due to anovervoltage. As a result, it may be inappropriate (or difficult) to usethe PS as an index/reference standard representing/indicating thecompatibility.

Wireless power transmitters and receivers may provide a very convenientuser experience and interface (UX/UI). That is, a smart wirelesscharging service may be provided, and the smart wireless chargingservice may be implemented based on a UX/UI of a smartphone including awireless power transmitter. For these applications, an interface betweena processor of a smartphone and a wireless charging receiver allows for“drop and play” two-way communication between the wireless powertransmitter and the wireless power receiver.

As an example, a user may experience a smart wireless charging servicein a hotel. When the user enters a hotel room and puts a smartphone on awireless charger in the room, the wireless charger transmits wirelesspower to the smartphone and the smartphone receives wireless power. Inthis process, the wireless charger transmits information on the smartwireless charging service to the smartphone. When it is detected thatthe smartphone is located on the wireless charger, when it is detectedthat wireless power is received, or when the smartphone receivesinformation on the smart wireless charging service from the wirelesscharger, the smartphone enters a state of inquiring the user aboutagreement (opt-in) of supplemental features. To this end, the smartphonemay display a message on a screen in a manner with or without an alarmsound. An example of the message may include the phrase “Welcome to ###hotel. Select” Yes “to activate smart charging functions: Yes|NoThanks.” The smartphone receives an input from the user who selects Yesor No Thanks, and performs a next procedure selected by the user. If Yesis selected, the smartphone transmits corresponding information to thewireless charger. The smartphone and the wireless charger perform thesmart charging function together.

The smart wireless charging service may also include receiving WiFicredentials auto-filled. For example, the wireless charger transmits theWiFi credentials to the smartphone, and the smartphone automaticallyinputs the WiFi credentials received from the wireless charger byrunning an appropriate application.

The smart wireless charging service may also include running a hotelapplication that provides hotel promotions or obtaining remotecheck-in/check-out and contact information.

As another example, the user may experience the smart wireless chargingservice in a vehicle. When the user gets in the vehicle and puts thesmartphone on the wireless charger, the wireless charger transmitswireless power to the smartphone and the smartphone receives wirelesspower. In this process, the wireless charger transmits information onthe smart wireless charging service to the smartphone. When it isdetected that the smartphone is located on the wireless charger, whenwireless power is detected to be received, or when the smartphonereceives information on the smart wireless charging service from thewireless charger, the smartphone enters a state of inquiring the userabout checking identity.

In this state, the smartphone is automatically connected to the vehiclevia WiFi and/or Bluetooth. The smartphone may display a message on thescreen in a manner with or without an alarm sound. An example of themessage may include a phrase of “Welcome to your car. Select “Yes” tosynch device with in-car controls: Yes No Thanks.” Upon receiving theuser's input to select Yes or No Thanks, the smartphone performs a nextprocedure selected by the user. If Yes is selected, the smartphonetransmits corresponding information to the wireless charger. Inaddition, the smartphone and the wireless charger may run an in-vehiclesmart control function together by driving in-vehicleapplication/display software. The user may enjoy the desired music andcheck a regular map location. The in-vehicle applications/displaysoftware may include an ability to provide synchronous access forpassers-by.

As another example, the user may experience smart wireless charging athome. When the user enters the room and puts the smartphone on thewireless charger in the room, the wireless charger transmits wirelesspower to the smartphone and the smartphone receives wireless power. Inthis process, the wireless charger transmits information on the smartwireless charging service to the smartphone. When it is detected thatthe smartphone is located on the wireless charger, when wireless poweris detected to be received, or when the smartphone receives informationon the smart wireless charging service from the wireless charger, thesmartphone enters a state of inquiring the user about agreement (opt-in)of supplemental features. To this end, the smartphone may display amessage on the screen in a manner with or without an alarm sound. Anexample of the message may include a phrase such as “Hi xxx, Would youlike to activate night mode and secure the building?: Yes No Thanks.”The smartphone receives a user input to select Yes or No Thanks andperforms a next procedure selected by the user. If Yes is selected, thesmartphone transmits corresponding information to the wireless charger.The smartphones and the wireless charger may recognize at least user'spattern and recommend the user to lock doors and windows, turn offlights, or set an alarm.

Hereinafter, ‘profiles’ will be newly defined based on indexes/referencestandards representing/indicating the compatibility. More specifically,it may be understood that by maintaining compatibility between wirelesspower transmitters and receivers having the same ‘profile’, stable powertransfer/reception may be performed, and that power transfer/receptionbetween wireless power transmitters and receivers having different‘profiles’ cannot be performed. The ‘profiles’ may be defined inaccordance with whether or not compatibility is possible and/or theapplication regardless of (or independent from) the power class.

For example, the profile may be sorted into 3 different categories, suchas i) Mobile, ii) Power tool and iii) Kitchen.

For another example, the profile may be sorted into 4 differentcategories, such as i) Mobile, ii) Power tool, iii) Kitchen, and iv)Wearable.

In case of the ‘Mobile’ profile, the PC may be defined as PC0 and/orPC1, the communication protocol/method may be defined as IB and OBcommunication, and the operation frequency may be defined as 87 to 205kHz, and smartphones, laptop computers, and so on, may exist as theexemplary application.

In case of the ‘Power tool’ profile, the PC may be defined as PC1, thecommunication protocol/method may be defined as IB communication, andthe operation frequency may be defined as 87 to 145 kHz, and powertools, and so on, may exist as the exemplary application.

In case of the ‘Kitchen’ profile, the PC may be defined as PC2, thecommunication protocol/method may be defined as NFC-based communication,and the operation frequency may be defined as less than 100 kHz, andkitchen/home appliances, and so on, may exist as the exemplaryapplication.

In the case of power tools and kitchen profiles, NFC communication maybe used between the wireless power transmitter and the wireless powerreceiver. The wireless power transmitter and the wireless power receivermay confirm that they are NFC devices with each other by exchanging WPCNFC data exchange profile format (NDEF). The WPC NDEF may include, forexample, an application profile field (e.g., 1B), a version field (e.g.,1B), and profile specific data (e.g., 1B). The application profile fieldindicates whether the corresponding device is i) mobile and computing,ii) power tool, and iii) kitchen, and an upper nibble in the versionfield indicates a major version and a lower nibble indicates a minorversion. In addition, profile-specific data defines content for thekitchen.

In case of the ‘Wearable’ profile, the PC may be defined as PC-1, thecommunication protocol/method may be defined as IB communication, andthe operation frequency may be defined as 87 to 205 kHz, and wearabledevices that are worn by the users, and so on, may exist as theexemplary application.

It may be mandatory to maintain compatibility between the same profiles,and it may be optional to maintain compatibility between differentprofiles.

The above-described profiles (Mobile profile, Power tool profile,Kitchen profile, and Wearable profile) may be generalized and expressedas first to nth profile, and a new profile may be added/replaced inaccordance with the WPC standard and the exemplary embodiment.

In case the profile is defined as described above, the wireless powertransmitter may optionally perform power transfer only to the wirelesspower receiving corresponding to the same profile as the wireless powertransmitter, thereby being capable of performing a more stable powertransfer. Additionally, since the load (or burden) of the wireless powertransmitter may be reduced and power transfer is not attempted to awireless power receiver for which compatibility is not possible, therisk of damage in the wireless power receiver may be reduced.

PC1 of the ‘Mobile’ profile may be defined by being derived from anoptional extension, such as OB, based on PC0. And, the ‘Power tool’profile may be defined as a simply modified version of the PC1 ‘Mobile’profile. Additionally, up until now, although the profiles have beendefined for the purpose of maintaining compatibility between the sameprofiles, in the future, the technology may be evolved to a level ofmaintaining compatibility between different profiles. The wireless powertransmitter or the wireless power receiver may notify (or announce) itsprofile to its counterpart by using diverse methods.

In the AFA standard, the wireless power transmitter is referred to as apower transmitting unit (PTU), and the wireless power receiver isreferred to as a power receiving unit (PRU). And, the PTU is categorizedto multiple classes, as shown in Table 1, and the PRU is categorized tomultiple classes, as shown in Table 2.

TABLE 1 Minimum Minimum value P_(TX)_ category for a maximum _(IN)_support number of supported PTU _(MAX) requirement devices Class 1  2W1x Category 1 1x Category 1 Class 2 10W 1x Category 3 2x Category 2Class 3 16W 1x Category 4 2x Category 3 Class 4 33W 1x Category 5 3xCategory 3 Class 5 50W 1x Category 6 4x Category 3 Class 6 70W 1xCategory 7 5x Category 3

TABLE 2 PRU P_(RX)_OUT_MAX′ Exemplary application Category 1 TBDBluetooth headset Category 2  3.5 W Feature phone Category 3  6.5 WSmartphone Category 4   13 W Tablet PC, Phablet Category 5   25 W Smallform factor laptop Category 6 37.5 W General laptop Category 7   50 WHome appliance

As shown in Table 1, a maximum output power capability of Class n PTUmay be equal to or greater than the R_(TX_IN_MAX) of the correspondingclass. The PRU cannot draw a power that is higher than the power levelspecified in the corresponding category.

FIG. 4a is a block diagram of a wireless power transfer system accordingto another exemplary embodiment of the present disclosure.

Referring to FIG. 4a , the wireless power transfer system (10) includesa mobile device (450), which wirelessly receives power, and a basestation (400), which wirelessly transmits power.

As a device providing induction power or resonance power, the basestation (400) may include at least one of a wireless power transmitter(100) and a system unit (405). The wireless power transmitter (100) maytransmit induction power or resonance power and may control thetransmission. The wireless power transmitter (100) may include a powerconversion unit (110) converting electric energy to a power signal bygenerating a magnetic field through a primary coil (or primary coils),and a communications & control unit (120) controlling the communicationand power transfer between the wireless power receiver (200) in order totransfer power at an appropriate (or suitable) level. The system unit(405) may perform input power provisioning, controlling of multiplewireless power transmitters, and other operation controls of the basestation (400), such as user interface control.

The primary coil may generate an electromagnetic field by using analternating current power (or voltage or current). The primary coil issupplied with an alternating current power (or voltage or current) of aspecific frequency, which is being outputted from the power conversionunit (110). And, accordingly, the primary coil may generate a magneticfield of the specific frequency. The magnetic field may be generated ina non-radial shape or a radial shape. And, the wireless power receiver(200) receives the generated magnetic field and then generates anelectric current. In other words, the primary coil wirelessly transmitspower.

In the magnetic induction method, a primary coil and a secondary coilmay have randomly appropriate shapes. For example, the primary coil andthe secondary coil may correspond to copper wire being wound around ahigh-permeability formation, such as ferrite or a non-crystalline metal.The primary coil may also be referred to as a transmitting coil, aprimary core, a primary winding, a primary loop antenna, and so on.Meanwhile, the secondary coil may also be referred to as a receivingcoil, a secondary core, a secondary winding, a secondary loop antenna, apickup antenna, and so on.

In case of using the magnetic resonance method, the primary coil and thesecondary coil may each be provided in the form of a primary resonanceantenna and a secondary resonance antenna. The resonance antenna mayhave a resonance structure including a coil and a capacitor. At thispoint, the resonance frequency of the resonance antenna may bedetermined by the inductance of the coil and a capacitance of thecapacitor. Herein, the coil may be formed to have a loop shape. And, acore may be placed inside the loop. The core may include a physicalcore, such as a ferrite core, or an air core.

The energy transmission (or transfer) between the primary resonanceantenna and the second resonance antenna may be performed by a resonancephenomenon occurring in the magnetic field. When a near fieldcorresponding to a resonance frequency occurs in a resonance antenna,and in case another resonance antenna exists near the correspondingresonance antenna, the resonance phenomenon refers to a highly efficientenergy transfer occurring between the two resonance antennas that arecoupled with one another. When a magnetic field corresponding to theresonance frequency is generated between the primary resonance antennaand the secondary resonance antenna, the primary resonance antenna andthe secondary resonance antenna resonate with one another. And,accordingly, in a general case, the magnetic field is focused toward thesecond resonance antenna at a higher efficiency as compared to a casewhere the magnetic field that is generated from the primary antenna isradiated to a free space. And, therefore, energy may be transferred tothe second resonance antenna from the first resonance antenna at a highefficiency. The magnetic induction method may be implemented similarlyto the magnetic resonance method. However, in this case, the frequencyof the magnetic field is not required to be a resonance frequency.Nevertheless, in the magnetic induction method, the loops configuringthe primary coil and the secondary coil are required to match oneanother, and the distance between the loops should be very close-ranged.

Although it is not shown in the drawing, the wireless power transmitter(100) may further include a communication antenna. The communicationantenna may transmit and/or receive a communication signal by using acommunication carrier apart from the magnetic field communication. Forexample, the communication antenna may transmit and/or receivecommunication signals corresponding to Wi-Fi, Bluetooth, Bluetooth LE,ZigBee, NFC, and so on.

The communications & control unit (120) may transmit and/or receiveinformation to and from the wireless power receiver (200). Thecommunications & control unit (120) may include at least one of an IBcommunication module and an OB communication module.

The IB communication module may transmit and/or receive information byusing a magnetic wave, which uses a specific frequency as its centerfrequency. For example, the communications & control unit (120) mayperform in-band (TB) communication by transmitting information on themagnetic wave through the primary coil or by receiving information onthe magnetic wave through the primary coil. At this point, thecommunications & control unit (120) may load information in the magneticwave or may interpret the information that is carried by the magneticwave by using a modulation scheme, such as binary phase shift keying(BPSK) or amplitude shift keying (ASK), and so on, or a coding scheme,such as Manchester coding or non-return-to-zero level (NZR-L) coding,and so on. By using the above-described TB communication, thecommunications & control unit (120) may transmit and/or receiveinformation to distances of up to several meters at a data transmissionrate of several kbps.

The OB communication module may also perform out-of-band communicationthrough a communication antenna. For example, the communications &control unit (120) may be provided to a near field communication module.Examples of the near field communication module may includecommunication modules, such as Wi-Fi, Bluetooth, Bluetooth LE, ZigBee,NFC, and so on.

The communications & control unit (120) may control the overalloperations of the wireless power transmitter (100). The communications &control unit (120) may perform calculation and processing of diverseinformation and may also control each configuration element of thewireless power transmitter (100).

The communications & control unit (120) may be implemented in a computeror a similar device as hardware, software, or a combination of the same.When implemented in the form of hardware, the communications & controlunit (120) may be provided as an electronic circuit performing controlfunctions by processing electrical signals. And, when implemented in theform of software, the communications & control unit (120) may beprovided as a program that operates the communications & control unit(120).

By controlling the operating point, the communications & control unit(120) may control the transmitted power. The operating point that isbeing controlled may correspond to a combination of a frequency (orphase), a duty cycle, a duty ratio, and a voltage amplitude. Thecommunications & control unit (120) may control the transmitted power byadjusting any one of the frequency (or phase), the duty cycle, the dutyratio, and the voltage amplitude. Additionally, the wireless powertransmitter (100) may supply a consistent level of power, and thewireless power receiver (200) may control the level of received power bycontrolling the resonance frequency.

The mobile device (450) includes a wireless power receiver (200)receiving wireless power through a secondary coil, and a load (455)receiving and storing the power that is received by the wireless powerreceiver (200) and supplying the received power to the device.

The wireless power receiver (200) may include a power pick-up unit (210)and a communications & control unit (220). The power pick-up unit (210)may receive wireless power through the secondary coil and may convertthe received wireless power to electric energy. The power pick-up unit(210) rectifies the alternating current (AC) signal, which is receivedthrough the secondary coil, and converts the rectified signal to adirect current (DC) signal. The communications & control unit (220) maycontrol the transmission and reception of the wireless power (transferand reception of power).

The secondary coil may receive wireless power that is being transmittedfrom the wireless power transmitter (100). The secondary coil mayreceive power by using the magnetic field that is generated in theprimary coil. Herein, in case the specific frequency corresponds aresonance frequency, magnetic resonance may occur between the primarycoil and the secondary coil, thereby allowing power to be transferredwith greater efficiency.

Although it is not shown in FIG. 4a , the communications & control unit(220) may further include a communication antenna. The communicationantenna may transmit and/or receive a communication signal by using acommunication carrier apart from the magnetic field communication. Forexample, the communication antenna may transmit and/or receivecommunication signals corresponding to Wi-Fi, Bluetooth, Bluetooth LE,ZigBee, NFC, and so on.

The communications & control unit (220) may transmit and/or receiveinformation to and from the wireless power transmitter (100). Thecommunications & control unit (220) may include at least one of an IBcommunication module and an OB communication module.

The IB communication module may transmit and/or receive information byusing a magnetic wave, which uses a specific frequency as its centerfrequency. For example, the communications & control unit (220) mayperform IB communication by loading information in the magnetic wave andby transmitting the information through the secondary coil or byreceiving a magnetic wave carrying information through the secondarycoil. At this point, the communications & control unit (120) may loadinformation in the magnetic wave or may interpret the information thatis carried by the magnetic wave by using a modulation scheme, such asbinary phase shift keying (BPSK) or amplitude shift keying (ASK), and soon, or a coding scheme, such as Manchester coding or non-return-to-zerolevel (NZR-L) coding, and so on. By using the above-described IBcommunication, the communications & control unit (220) may transmitand/or receive information to distances of up to several meters at adata transmission rate of several kbps.

The OB communication module may also perform out-of-band communicationthrough a communication antenna. For example, the communications &control unit (220) may be provided to a near field communication module.

Examples of the near field communication module may includecommunication modules, such as Wi-Fi, Bluetooth, Bluetooth LE, ZigBee,NFC, and so on.

The communications & control unit (220) may control the overalloperations of the wireless power receiver (200). The communications &control unit (220) may perform calculation and processing of diverseinformation and may also control each configuration element of thewireless power receiver (200).

The communications & control unit (220) may be implemented in a computeror a similar device as hardware, software, or a combination of the same.When implemented in the form of hardware, the communications & controlunit (220) may be provided as an electronic circuit performing controlfunctions by processing electrical signals. And, when implemented in theform of software, the communications & control unit (220) may beprovided as a program that operates the communications & control unit(220).

When the communication/control circuit 120 and the communication/controlcircuit 220 are Bluetooth or Bluetooth LE as an OB communication moduleor a short-range communication module, the communication/control circuit120 and the communication/control circuit 220 may each be implementedand operated with a communication architecture as shown in FIG. 4B.

FIG. 4B is a diagram illustrating an example of a Bluetoothcommunication architecture to which an embodiment according to thepresent disclosure may be applied.

Referring to FIG. 4B, (a) of FIG. 4B shows an example of a protocolstack of Bluetooth basic rate (BR)/enhanced data rate (EDR) supportingGATT, and (b) shows an example of Bluetooth low energy (BLE) protocolstack.

Specifically, as shown in (a) of FIG. 4B, the Bluetooth BR/EDR protocolstack may include an upper control stack 460 and a lower host stack 470based on a host controller interface (HCI) 18.

The host stack (or host module) 470 refers to hardware for transmittingor receiving a Bluetooth packet to or from a wirelesstransmission/reception module which receives a Bluetooth signal of 2.4GHz, and the controller stack 460 is connected to the Bluetooth moduleto control the Bluetooth module and perform an operation.

The host stack 470 may include a BR/EDR PHY layer 12, a BR/EDR basebandlayer 14, and a link manager layer 16.

The BR/EDR PHY layer 12 is a layer that transmits and receives a 2.4 GHzradio signal, and in the case of using Gaussian frequency shift keying(GFSK) modulation, the BR/EDR PHY layer 12 may transmit data by hopping79 RF channels.

The BR/EDR baseband layer 14 serves to transmit a digital signal,selects a channel sequence for hopping 1400 times per second, andtransmits a time slot with a length of 625 us for each channel.

The link manager layer 16 controls an overall operation (link setup,control, security) of Bluetooth connection by utilizing a link managerprotocol (LMP).

The link manager layer 16 may perform the following functions.

-   -   Performs ACL/SCO logical transport, logical link setup, and        control.    -   Detach: It interrupts connection and informs a counterpart        device about a reason for the interruption.    -   Performs power control and role switch.    -   Performs security (authentication, pairing, encryption)        function.

The host controller interface layer 18 provides an interface between ahost module and a controller module so that a host provides commands anddata to the controller and the controller provides events and data tothe host.

The host stack (or host module, 470) includes a logical link control andadaptation protocol (L2CAP) 21, an attribute protocol 22, a genericattribute profile (GATT) 23, a generic access profile (GAP) 24, and aBR/EDR profile 25.

The logical link control and adaptation protocol (L2CAP) 21 may provideone bidirectional channel for transmitting data to a specific protocolor profile.

The L2CAP 21 may multiplex various protocols, profiles, etc., providedfrom upper Bluetooth.

L2CAP of Bluetooth BR/EDR uses dynamic channels, supports protocolservice multiplexer, retransmission, streaming mode, and providessegmentation and reassembly, per-channel flow control, and errorcontrol.

The generic attribute profile (GATT) 23 may be operable as a protocolthat describes how the attribute protocol 22 is used when services areconfigured. For example, the generic attribute profile 23 may beoperable to specify how ATT attributes are grouped together intoservices and may be operable to describe features associated withservices.

Accordingly, the generic attribute profile 23 and the attributeprotocols (ATT) 22 may use features to describe device's state andservices, how features are related to each other, and how they are used.

The attribute protocol 22 and the BR/EDR profile 25 define a service(profile) using Bluetooth BR/EDR and an application protocol forexchanging these data, and the generic access profile (GAP) 24 definesdevice discovery, connectivity, and security level.

As shown in (b) of FIG. 4B, the Bluetooth LE protocol stack includes acontroller stack 480 operable to process a wireless device interfaceimportant in timing and a host stack 490 operable to process high leveldata.

First, the controller stack 480 may be implemented using a communicationmodule that may include a Bluetooth wireless device, for example, aprocessor module that may include a processing device such as amicroprocessor.

The host stack 490 may be implemented as a part of an OS running on aprocessor module or as an instantiation of a package on the OS.

In some cases, the controller stack and the host stack may be run orexecuted on the same processing device in a processor module.

The controller stack 480 includes a physical layer (PHY) 32, a linklayer 34, and a host controller interface 36.

The physical layer (PHY, wireless transmission/reception module) 32 is alayer that transmits and receives a 2.4 GHz radio signal and usesGaussian frequency shift keying (GFSK) modulation and a frequencyhopping scheme including 40 RF channels.

The link layer 34, which serves to transmit or receive Bluetoothpackets, creates connections between devices after performingadvertising and scanning functions using 3 advertising channels andprovides a function of exchanging data packets of up to 257 bytesthrough 37 data channels.

The host stack includes a generic access profile (GAP) 45, a logicallink control and adaptation protocol (L2CAP, 41), a security manager(SM) 42, and an attribute protocol (ATT) 43, a generic attribute profile(GATT) 44, a generic access profile 45, and an LE profile 46. However,the host stack 490 is not limited thereto and may include variousprotocols and profiles.

The host stack multiplexes various protocols, profiles, etc., providedfrom upper Bluetooth using L2CAP.

First, the logical link control and adaptation protocol (L2CAP) 41 mayprovide one bidirectional channel for transmitting data to a specificprotocol or profile.

The L2CAP 41 may be operable to multiplex data between higher layerprotocols, segment and reassemble packages, and manage multicast datatransmission.

In Bluetooth LE, three fixed channels (one for signaling CH, one forsecurity manager, and one for attribute protocol) are basically used.Also, a dynamic channel may be used as needed.

Meanwhile, a basic channel/enhanced data rate (BR/EDR) uses a dynamicchannel and supports protocol service multiplexer, retransmission,streaming mode, and the like.

The security manager (SM) 42 is a protocol for authenticating devicesand providing key distribution.

The attribute protocol (ATT) 43 defines a rule for accessing data of acounterpart device in a server-client structure. The ATT has thefollowing 6 message types (request, response, command, notification,indication, confirmation).

{circle around (1)} Request and Response message: A request message is amessage for requesting specific information from the client device tothe server device, and the response message is a response message to therequest message, which is a message transmitted from the server deviceto the client device.

{circle around (2)} Command message: It is a message transmitted fromthe client device to the server device in order to indicate a command ofa specific operation. The server device does not transmit a responsewith respect to the command message to the client device.

{circle around (3)} Notification message: It is a message transmittedfrom the server device to the client device in order to notify an event,or the like. The client device does not transmit a confirmation messagewith respect to the notification message to the server device.

{circle around (4)} Indication and confirmation message: It is a messagetransmitted from the server device to the client device in order tonotify an event, or the like. Unlike the notification message, theclient device transmits a confirmation message regarding the indicationmessage to the server device.

In the present disclosure, when the GATT profile using the attributeprotocol (ATT) 43 requests long data, a value regarding a data length istransmitted to allow a client to clearly know the data length, and acharacteristic value may be received from a server by using a universalunique identifier (UUID).

The generic access profile (GAP) 45, a layer newly implemented for theBluetooth LE technology, is used to select a role for communicationbetween Bluetooth LED devices and to control how a multi-profileoperation takes place.

Also, the generic access profile (GAP) 45 is mainly used for devicediscovery, connection generation, and security procedure part, defines ascheme for providing information to a user, and defines types ofattributes as follows.

{circle around (1)} Service: It defines a basic operation of a device bya combination of behaviors related to data

{circle around (2)} Include: It defines a relationship between services

{circle around (3)} Characteristics: It is a data value used in a server

{circle around (4)} Behavior: It is a format that may be read by acomputer defined by a UUID (value type).

The LE profile 46, including profiles dependent upon the GATT, is mainlyapplied to a Bluetooth LE device. The LE profile 46 may include, forexample, Battery, Time, FindMe, Proximity, Time, Object DeliveryService, and the like, and details of the GATT-based profiles are asfollows.

{circle around (1)} Battery: Battery information exchanging method

{circle around (2)} Time: Time information exchanging method

{circle around (3)} FindMe: Provision of alarm service according todistance

{circle around (4)} Proximity: Battery information exchanging method

{circle around (5)} Time: Time information exchanging method

The generic attribute profile (GATT) 44 may operate as a protocoldescribing how the attribute protocol (ATT) 43 is used when services areconfigured. For example, the GATT 44 may operate to define how ATTattributes are grouped together with services and operate to describefeatures associated with services.

Thus, the GATT 44 and the ATT 43 may use features in order to describestatus and services of a device and describe how the features arerelated and used.

Hereinafter, procedures of the Bluetooth low energy (BLE) technologywill be briefly described.

The BLE procedure may be classified as a device filtering procedure, anadvertising procedure, a scanning procedure, a discovering procedure,and a connecting procedure.

Device Filtering Procedure

The device filtering procedure is a method for reducing the number ofdevices performing a response with respect to a request, indication,notification, and the like, in the controller stack.

When requests are received from all the devices, it is not necessary torespond thereto, and thus, the controller stack may perform control toreduce the number of transmitted requests to reduce power consumption.

An advertising device or scanning device may perform the devicefiltering procedure to limit devices for receiving an advertisingpacket, a scan request or a connection request.

Here, the advertising device refers to a device transmitting anadvertising event, that is, a device performing an advertisement and isalso termed an advertiser.

The scanning device refers to a device performing scanning, that is, adevice transmitting a scan request.

In the BLE, in a case in which the scanning device receives someadvertising packets from the advertising device, the scanning deviceshould transmit a scan request to the advertising device.

However, in a case in which a device filtering procedure is used so ascan request transmission is not required, the scanning device maydisregard the advertising packets transmitted from the advertisingdevice.

Even in a connection request process, the device filtering procedure maybe used. In a case in which device filtering is used in the connectionrequest process, it is not necessary to transmit a response with respectto the connection request by disregarding the connection request.

Advertising Procedure

The advertising device performs an advertising procedure to performundirected broadcast to devices within a region.

Here, the undirected broadcast is advertising toward all the devices,rather than broadcast toward a specific device, and all the devices mayscan advertising to make an supplemental information request or aconnection request.

In contrast, directed advertising may make an supplemental informationrequest or a connection request by scanning advertising for only adevice designated as a reception device.

The advertising procedure is used to establish a Bluetooth connectionwith an initiating device nearby.

Or, the advertising procedure may be used to provide periodicalbroadcast of user data to scanning devices performing listening in anadvertising channel.

In the advertising procedure, all the advertisements (or advertisingevents) are broadcast through an advertisement physical channel.

The advertising devices may receive scan requests from listening devicesperforming listening to obtain additional user data from advertisingdevices. The advertising devices transmit responses with respect to thescan requests to the devices which have transmitted the scan requests,through the same advertising physical channels as the advertisingphysical channels in which the scan requests have been received.

Broadcast user data sent as part of advertising packets are dynamicdata, while the scan response data is generally static data.

The advertisement device may receive a connection request from aninitiating device on an advertising (broadcast) physical channel. If theadvertising device has used a connectable advertising event and theinitiating device has not been filtered according to the devicefiltering procedure, the advertising device may stop advertising andenter a connected mode. The advertising device may start advertisingafter the connected mode.

Scanning Procedure

A device performing scanning, that is, a scanning device performs ascanning procedure to listen to undirected broadcasting of user datafrom advertising devices using an advertising physical channel.

The scanning device transmits a scan request to an advertising devicethrough an advertising physical channel in order to request additionaldata from the advertising device. The advertising device transmits ascan response as a response with respect to the scan request, byincluding additional user data which has requested by the scanningdevice through an advertising physical channel.

The scanning procedure may be used while being connected to other BLEdevice in the BLE piconet.

If the scanning device is in an initiator mode in which the scanningdevice may receive an advertising event and initiates a connectionrequest. The scanning device may transmit a connection request to theadvertising device through the advertising physical channel to start aBluetooth connection with the advertising device.

When the scanning device transmits a connection request to theadvertising device, the scanning device stops the initiator modescanning for additional broadcast and enters the connected mode.

Discovering Procedure

Devices available for Bluetooth communication (hereinafter, referred toas “Bluetooth devices”) perform an advertising procedure and a scanningprocedure in order to discover devices located nearby or in order to bediscovered by other devices within a given area.

The discovering procedure is performed asymmetrically. A Bluetoothdevice intending to discover other device nearby is termed a discoveringdevice, and listens to discover devices advertising an advertising eventthat may be scanned. A Bluetooth device which may be discovered by otherdevice and available to be used is termed a discoverable device andpositively broadcasts an advertising event such that it may be scannedby other device through an advertising (broadcast) physical channel.

Both the discovering device and the discoverable device may have alreadybeen connected with other Bluetooth devices in a piconet.

Connecting Procedure

A connecting procedure is asymmetrical, and requests that, while aspecific Bluetooth device is performing an advertising procedure,another Bluetooth device should perform a scanning procedure.

That is, an advertising procedure may be aimed, and as a result, onlyone device may response to the advertising. After a connectableadvertising event is received from an advertising device, a connectingrequest may be transmitted to the advertising device through anadvertising (broadcast) physical channel to initiate connection.

Hereinafter, operational states, that is, an advertising state, ascanning state, an initiating state, and a connection state, in the BLEtechnology will be briefly described.

Advertising State

A link layer (LL) enters an advertising state according to aninstruction from a host (stack). In a case in which the LL is in theadvertising state, the LL transmits an advertising packet data unit(PDU) in advertising events.

Each of the advertising events include at least one advertising PDU, andthe advertising PDU is transmitted through an advertising channel indexin use. After the advertising PDU is transmitted through an advertisingchannel index in use, the advertising event may be terminated, or in acase in which the advertising device may need to secure a space forperforming other function, the advertising event may be terminatedearlier.

Scanning State

The LL enters the scanning state according to an instruction from thehost (stack). In the scanning state, the LL listens to advertisingchannel indices.

The scanning state includes two types: passive scanning and activescanning. Each of the scanning types is determined by the host.

Time for performing scanning or an advertising channel index are notdefined.

During the scanning state, the LL listens to an advertising channelindex in a scan window duration. A scan interval is defined as aninterval between start points of two continuous scan windows.

When there is no collision in scheduling, the LL should listen in orderto complete all the scan intervals of the scan window as instructed bythe host. In each scan window, the LL should scan other advertisingchannel index. The LL uses every available advertising channel index.

In the passive scanning, the LL only receives packets and cannottransmit any packet.

In the active scanning, the LL performs listening in order to be reliedon an advertising PDU type for requesting advertising PDUs andadvertising device-related supplemental information from the advertisingdevice.

Initiating State

The LL enters the initiating state according to an instruction from thehost (stack).

When the LL is in the initiating state, the LL performs listening onadvertising channel indices.

During the initiating state, the LL listens to an advertising channelindex during the scan window interval.

Connection State

When the device performing a connection state, that is, when theinitiating device transmits a CONNECT_REQ PDU to the advertising deviceor when the advertising device receives a CONNECT_REQ PDU from theinitiating device, the LL enters a connection state.

It is considered that a connection is generated after the LL enters theconnection state. However, it is not necessary to consider that theconnection should be established at a point in time at which the LLenters the connection state. The only difference between a newlygenerated connection and an already established connection is a LLconnection supervision timeout value.

When two devices are connected, the two devices play different roles.

An LL serving as a master is termed a master, and an LL serving as aslave is termed a slave. The master adjusts a timing of a connectingevent, and the connecting event refers to a point in time at which themaster and the slave are synchronized.

Hereinafter, packets defined in an Bluetooth interface will be brieflydescribed. BLE devices use packets defined as follows.

Packet Format

The LL has only one packet format used for both an advertising channelpacket and a data channel packet.

Each packet includes four fields of a preamble, an access address, aPDU, and a CRC.

When one packet is transmitted in an advertising physical channel, thePDU may be an advertising channel PDU, and when one packet istransmitted in a data physical channel, the PDU may be a data channelPDU.

Advertising Channel PDU

An advertising channel PDU has a 16-bit header and payload havingvarious sizes.

A PDU type field of the advertising channel PDU included in the heaterindicates PDU types defined in Table 3 below.

TABLE 3 PDU Type Packet Name 0000 ADV_IND 0001 ADV_DIRECT_IND 0010ADV_NONCONN_IND 0011 SCAN_REQ 0100 SCAN_RSP 0101 CONNECT_REQ 0110ADV_SCAN_IND 0111-1111 Reserved

Advertising PDU

The following advertising channel PDU types are termed advertising PDUsand used in a specific event.

ADV_IND: Connectable undirected advertising event

ADV_DIRECT_IND: Connectable directed advertising event

ADV_NONCONN_IND: Unconnectable undirected advertising event

ADV_SCAN_IND: Scannable undirected advertising event

The PDUs are transmitted from the LL in an advertising state, andreceived by the LL in a scanning state or in an initiating state.

Scanning PDU

The following advertising channel DPU types are termed scanning PDUs andare used in a state described hereinafter.

SCAN_REQ: Transmitted by the LL in a scanning state and received by theLL in an advertising state.

SCAN_RSP: Transmitted by the LL in the advertising state and received bythe LL in the scanning state.

Initiating PDU

The following advertising channel PDU type is termed an initiating PDU.

CONNECT_REQ: Transmitted by the LL in the initiating state and receivedby the LL in the advertising state.

Data Channel PDU

The data channel PDU may include a message integrity check (MIC) fieldhaving a 16-bit header and payload having various sizes.

The procedures, states, and packet formats in the BLE technologydiscussed above may be applied to perform the methods proposed in thepresent disclosure.

Referring to FIG. 4a , The load (455) may correspond to a battery. Thebattery may store energy by using the power that is being outputted fromthe power pick-up unit (210). Meanwhile, the battery is not mandatorilyrequired to be included in the mobile device (450). For example, thebattery may be provided as a detachable external feature. As anotherexample, the wireless power receiver may include an operating means thatmay execute diverse functions of the electronic device instead of thebattery.

As shown in the drawing, although the mobile device (450) is illustratedto be included in the wireless power receiver (200) and the base station(400) is illustrated to be included in the wireless power transmitter(100), in a broader meaning, the wireless power receiver (200) may beidentified (or regarded) as the mobile device (450), and the wirelesspower transmitter (100) may be identified (or regarded) as the basestation (400).

When the communication/control circuit 120 and the communication/controlcircuit 220 include Bluetooth or Bluetooth LE as an OB communicationmodule or a short-range communication module in addition to the IBcommunication module, the wireless power transmitter 100 including thecommunication/control circuit 120 and the wireless power receiver 200including the communication/control circuit 220 may be represented by asimplified block diagram as shown in FIG. 4C.

FIG. 4C is a block diagram illustrating a wireless power transfer systemusing BLE communication according to an example.

Referring to FIG. 4C, the wireless power transmitter 100 includes apower conversion circuit 110 and a communication/control circuit 120.The communication/control circuit 120 includes an in-band communicationmodule 121 and a BLE communication module 122.

Meanwhile, the wireless power receiver 200 includes a power pickupcircuit 210 and a communication/control circuit 220. Thecommunication/control circuit 220 includes an in-band communicationmodule 221 and a BLE communication module 222.

In one aspect, the BLE communication modules 122 and 222 perform thearchitecture and operation according to FIG. 4B. For example, the BLEcommunication modules 122 and 222 may be used to establish a connectionbetween the wireless power transmitter 100 and the wireless powerreceiver 200 and exchange control information and packets necessary forwireless power transfer.

In another aspect, the communication/control circuit 120 may beconfigured to operate a profile for wireless charging. Here, the profilefor wireless charging may be GATT using BLE transmission.

Referring to FIG. 4D, the communication/control circuits 120 and 220respectively include only in-band communication modules 121 and 221, andthe BLE communication modules 122 and 222 may be provided to beseparated from the communication/control circuits 120 and 220.

Hereinafter, the coil or coil unit includes a coil and at least onedevice being approximate to the coil, and the coil or coil unit may alsobe referred to as a coil assembly, a coil cell, or a cell.

FIG. 5 is a state transition diagram for describing a wireless powertransfer procedure.

Referring to FIG. 5, the power transfer (or transfer) from the wirelesspower transmitter to the wireless power receiver according to anexemplary embodiment of the present disclosure may be broadly dividedinto a selection phase (510), a ping phase (520), an identification andconfiguration phase (530), a negotiation phase (540), a calibrationphase (550), a power transfer phase (560), and a renegotiation phase(570).

If a specific error or a specific event is detected when the powertransfer is initiated or while maintaining the power transfer, theselection phase (510) may include a shifting phase (or step)—referencenumerals S502, S504, S508, S510, and S512. Herein, the specific error orspecific event will be specified in the following description.Additionally, during the selection phase (510), the wireless powertransmitter may monitor whether or not an object exists on an interfacesurface. If the wireless power transmitter detects that an object isplaced on the interface surface, the process step may be shifted to theping phase (520). During the selection phase (510), the wireless powertransmitter may transmit an analog ping having a power signal(or apulse) corresponding to an extremely short duration, and may detectwhether or not an object exists within an active area of the interfacesurface based on a current change in the transmitting coil or theprimary coil.

In case an object is sensed (or detected) in the selection phase (510),the wireless power transmitter may measure a quality factor of awireless power resonance circuit (e.g., power transfer coil and/orresonance capacitor). According to the exemplary embodiment of thepresent disclosure, during the selection phase (510), the wireless powertransmitter may measure the quality factor in order to determine whetheror not a foreign object exists in the charging area along with thewireless power receiver. In the coil that is provided in the wirelesspower transmitter, inductance and/or components of the series resistancemay be reduced due to a change in the environment, and, due to suchdecrease, a value of the quality factor may also be decreased. In orderto determine the presence or absence of a foreign object by using themeasured quality factor value, the wireless power transmitter mayreceive from the wireless power receiver a reference quality factorvalue, which is measured in advance in a state where no foreign objectis placed within the charging area. The wireless power transmitter maydetermine the presence or absence of a foreign object by comparing themeasured quality factor value with the reference quality factor value,which is received during the negotiation phase (540). However, in caseof a wireless power receiver having a low reference quality factorvalue—e.g., depending upon its type, purpose, characteristics, and soon, the wireless power receiver may have a low reference quality factorvalue—in case a foreign object exists, since the difference between thereference quality factor value and the measured quality factor value issmall (or insignificant), a problem may occur in that the presence ofthe foreign object cannot be easily determined. Accordingly, in thiscase, other determination factors should be further considered, or thepresent or absence of a foreign object should be determined by usinganother method.

According to another exemplary embodiment of the present disclosure, incase an object is sensed (or detected) in the selection phase (510), inorder to determine whether or not a foreign object exists in thecharging area along with the wireless power receiver, the wireless powertransmitter may measure the quality factor value within a specificfrequency area (e.g., operation frequency area). In the coil that isprovided in the wireless power transmitter, inductance and/or componentsof the series resistance may be reduced due to a change in theenvironment, and, due to such decrease, the resonance frequency of thecoil of the wireless power transmitter may be changed (or shifted). Morespecifically, a quality factor peak frequency that corresponds to afrequency in which a maximum quality factor value is measured within theoperation frequency band may be moved (or shifted).

In the ping phase (520), if the wireless power transmitter detects thepresence of an object, the transmitter activates (or Wakes up) areceiver and transmits a digital ping for identifying whether or not thedetected object corresponds to the wireless power receiver. During theping phase (520), if the wireless power transmitter fails to receive aresponse signal for the digital ping—e.g., a signal intensitypacket—from the receiver, the process may be shifted back to theselection phase (510). Additionally, in the ping phase (520), if thewireless power transmitter receives a signal indicating the completionof the power transfer—e.g., charging complete packet—from the receiver,the process may be shifted back to the selection phase (510).

If the ping phase (520) is completed, the wireless power transmitter mayshift to the identification and configuration phase (530) foridentifying the receiver and for collecting configuration and statusinformation.

In the identification and configuration phase (530), if the wirelesspower transmitter receives an unwanted packet (i.e., unexpected packet),or if the wireless power transmitter fails to receive a packet during apredetermined period of time (i.e., out of time), or if a packettransmission error occurs (i.e., transmission error), or if a powertransfer contract is not configured (i.e., no power transfer contract),the wireless power transmitter may shift to the selection phase (510).

The wireless power transmitter may confirm (or verify) whether or notits entry to the negotiation phase (540) is needed based on aNegotiation field value of the configuration packet, which is receivedduring the identification and configuration phase (530). Based on theverified result, in case a negotiation is needed, the wireless powertransmitter enters the negotiation phase (540) and may then perform apredetermined FOD detection procedure. Conversely, in case a negotiationis not needed, the wireless power transmitter may immediately enter thepower transfer phase (560).

In the negotiation phase (540), the wireless power transmitter mayreceive a Foreign Object Detection (FOD) status packet that includes areference quality factor value. Or, the wireless power transmitter mayreceive an FOD status packet that includes a reference peak frequencyvalue. Alternatively, the wireless power transmitter may receive astatus packet that includes a reference quality factor value and areference peak frequency value. At this point, the wireless powertransmitter may determine a quality coefficient threshold value for FOdetection based on the reference quality factor value. The wirelesspower transmitter may determine a peak frequency threshold value for FOdetection based on the reference peak frequency value.

The wireless power transmitter may detect the presence or absence of anFO in the charging area by using the determined quality coefficientthreshold value for FO detection and the currently measured qualityfactor value (i.e., the quality factor value that was measured beforethe ping phase), and, then, the wireless power transmitter may controlthe transmitted power in accordance with the FO detection result. Forexample, in case the FO is detected, the power transfer may be stopped.However, the present disclosure will not be limited only to this.

The wireless power transmitter may detect the presence or absence of anFO in the charging area by using the determined peak frequency thresholdvalue for FO detection and the currently measured peak frequency value(i.e., the peak frequency value that was measured before the pingphase), and, then, the wireless power transmitter may control thetransmitted power in accordance with the FO detection result. Forexample, in case the FO is detected, the power transfer may be stopped.However, the present disclosure will not be limited only to this.

In case the FO is detected, the wireless power transmitter may return tothe selection phase (510). Conversely, in case the FO is not detected,the wireless power transmitter may proceed to the calibration phase(550) and may, then, enter the power transfer phase (560). Morespecifically, in case the FO is not detected, the wireless powertransmitter may determine the intensity of the received power that isreceived by the receiving end during the calibration phase (550) and maymeasure power loss in the receiving end and the transmitting end inorder to determine the intensity of the power that is transmitted fromthe transmitting end. In other words, during the calibration phase(550), the wireless power transmitter may estimate the power loss basedon a difference between the transmitted power of the transmitting endand the received power of the receiving end. The wireless powertransmitter according to the exemplary embodiment of the presentdisclosure may calibrate the threshold value for the FOD detection byapplying the estimated power loss.

In the power transfer phase (560), in case the wireless powertransmitter receives an unwanted packet (i.e., unexpected packet), or incase the wireless power transmitter fails to receive a packet during apredetermined period of time (i.e., time-out), or in case a violation ofa predetermined power transfer contract occurs (i.e., power transfercontract violation), or in case charging is completed, the wirelesspower transmitter may shift to the selection phase (510).

Additionally, in the power transfer phase (560), in case the wirelesspower transmitter is required to reconfigure the power transfer contractin accordance with a status change in the wireless power transmitter,the wireless power transmitter may shift to the renegotiation phase(570). At this point, if the renegotiation is successfully completed,the wireless power transmitter may return to the power transfer phase(560).

In this embodiment, the calibration step 550 and the power transferphase 560 are divided into separate steps, but the calibration step 550may be integrated into the power transfer phase 560. In this case,operations in the calibration step 550 may be performed in the powertransfer phase 560.

The above-described power transfer contract may be configured based onthe status and characteristic information of the wireless powertransmitter and receiver. For example, the wireless power transmitterstatus information may include information on a maximum amount oftransmittable power, information on a maximum number of receivers thatmay be accommodated, and so on. And, the receiver status information mayinclude information on the required power, and so on.

FIG. 6 shows a power control method according to an exemplary embodimentof the present disclosure.

As shown in FIG. 6, in the power transfer phase (560), by alternatingthe power transfer and/or reception and communication, the wirelesspower transmitter (100) and the wireless power receiver (200) maycontrol the amount (or size) of the power that is being transferred. Thewireless power transmitter and the wireless power receiver operate at aspecific control point. The control point indicates a combination of thevoltage and the electric current that are provided from the output ofthe wireless power receiver, when the power transfer is performed.

More specifically, the wireless power receiver selects a desired controlpoint, a desired output current/voltage, a temperature at a specificlocation of the mobile device, and so on, and additionally determines anactual control point at which the receiver is currently operating. Thewireless power receiver calculates a control error value by using thedesired control point and the actual control point, and, then, thewireless power receiver may transmit the calculated control error valueto the wireless power transmitter as a control error packet.

Also, the wireless power transmitter may configure/control a newoperating point—amplitude, frequency, and duty cycle—by using thereceived control error packet, so as to control the power transfer.Therefore, the control error packet may be transmitted/received at aconstant time interval during the power transfer phase, and, accordingto the exemplary embodiment, in case the wireless power receiverattempts to reduce the electric current of the wireless powertransmitter, the wireless power receiver may transmit the control errorpacket by setting the control error value to a negative number. And, incase the wireless power receiver intends to increase the electriccurrent of the wireless power transmitter, the wireless power receivertransmit the control error packet by setting the control error value toa positive number. During the induction mode, by transmitting thecontrol error packet to the wireless power transmitter as describedabove, the wireless power receiver may control the power transfer.

In the resonance mode, which will hereinafter be described in detail,the device may be operated by using a method that is different from theinduction mode. In the resonance mode, one wireless power transmittershould be capable of serving a plurality of wireless power receivers atthe same time. However, in case of controlling the power transfer justas in the induction mode, since the power that is being transferred iscontrolled by a communication that is established with one wirelesspower receiver, it may be difficult to control the power transfer ofadditional wireless power receivers. Therefore, in the resonance modeaccording to the present disclosure, a method of controlling the amountof power that is being received by having the wireless power transmittercommonly transfer (or transmit) the basic power and by having thewireless power receiver control its own resonance frequency.Nevertheless, even during the operation of the resonance mode, themethod described above in FIG. 6 will not be completely excluded. And,additional control of the transmitted power may be performed by usingthe method of FIG. 6.

FIG. 7 is a block diagram of a wireless power transmitter according toanother exemplary embodiment of the present disclosure. This may belongto a wireless power transfer system that is being operated in themagnetic resonance mode or the shared mode. The shared mode may refer toa mode performing a several-for-one (or one-to-many) communication andcharging between the wireless power transmitter and the wireless powerreceiver. The shared mode may be implemented as a magnetic inductionmethod or a resonance method.

Referring to FIG. 7, the wireless power transmitter (700) may include atleast one of a cover (720) covering a coil assembly, a power adapter(730) supplying power to the power transmitter (740), a powertransmitter (740) transmitting wireless power, and a user interface(750) providing information related to power transfer processing andother related information. Most particularly, the user interface (750)may be optionally included or may be included as another user interface(750) of the wireless power transmitter (700).

The power transmitter (740) may include at least one of a coil assembly(760), an impedance matching circuit (770), an inverter (780), acommunication unit (790), and a control unit (710).

The coil assembly (760) includes at least one primary coil generating amagnetic field. And, the coil assembly (760) may also be referred to asa coil cell.

The impedance matching circuit (770) may provide impedance matchingbetween the inverter and the primary coil(s). The impedance matchingcircuit (770) may generate resonance from a suitable frequency thatboosts the electric current of the primary coil(s). In a multi-coilpower transmitter (740), the impedance matching circuit may additionallyinclude a multiplex that routes signals from the inverter to a subset ofthe primary coils. The impedance matching circuit may also be referredto as a tank circuit.

The impedance matching circuit (770) may include a capacitor, aninductor, and a switching device that switches the connection betweenthe capacitor and the inductor. The impedance matching may be performedby detecting a reflective wave of the wireless power that is beingtransferred (or transmitted) through the coil assembly (760) and byswitching the switching device based on the detected reflective wave,thereby adjusting the connection status of the capacitor or the inductoror adjusting the capacitance of the capacitor or adjusting theinductance of the inductor. In some cases, the impedance matching may becarried out even though the impedance matching circuit (770) is omitted.This specification also includes an exemplary embodiment of the wirelesspower transmitter (700), wherein the impedance matching circuit (770) isomitted.

The inverter (780) may convert a DC input to an AC signal. The inverter(780) may be operated as a half-bridge inverter or a full-bridgeinverter in order to generate a pulse wave and a duty cycle of anadjustable frequency. Additionally, the inverter may include a pluralityof stages in order to adjust input voltage levels.

The communication unit (790) may perform communication with the powerreceiver. The power receiver performs load modulation in order tocommunicate requests and information corresponding to the powertransmitter. Therefore, the power transmitter (740) may use thecommunication unit (790) so as to monitor the amplitude and/or phase ofthe electric current and/or voltage of the primary coil in order todemodulate the data being transmitted from the power receiver.

Additionally, the power transmitter (740) may control the output powerto that the data may be transferred through the communication unit (790)by using a Frequency Shift Keying (FSK) method, and so on.

The control unit (710) may control communication and power transfer (ordelivery) of the power transmitter (740). The control unit (710) maycontrol the power transfer by adjusting the above-described operatingpoint. The operating point may be determined by, for example, at leastany one of the operation frequency, the duty cycle, and the inputvoltage.

The communication unit (790) and the control unit (710) may each beprovided as a separate unit/device/chipset or may be collectivelyprovided as one unit/device/chipset.

FIG. 8 shows a wireless power receiver according to another exemplaryembodiment of the present disclosure. This may belong to a wirelesspower transfer system that is being operated in the magnetic resonancemode or the shared mode.

Referring to FIG. 8, the wireless power receiver (800) may include atleast one of a user interface (820) providing information related topower transfer processing and other related information, a powerreceiver (830) receiving wireless power, a load circuit (840), and abase (850) supporting and covering the coil assembly. Most particularly,the user interface (820) may be optionally included or may be includedas another user interface (820) of the wireless power receiver (800).

The power receiver (830) may include at least one of a power converter(860), an impedance matching circuit (870), a coil assembly (880), acommunication unit (890), and a control unit (810).

The power converter (860) may convert the AC power that is received fromthe secondary coil to a voltage and electric current that are suitablefor the load circuit. According to an exemplary embodiment, the powerconverter (860) may include a rectifier. The rectifier may rectify thereceived wireless power and may convert the power from an alternatingcurrent (AC) to a direct current (DC). The rectifier may convert thealternating current to the direct current by using a diode or atransistor, and, then, the rectifier may smooth the converted current byusing the capacitor and resistance. Herein, a full-wave rectifier, ahalf-wave rectifier, a voltage multiplier, and so on, that areimplemented as a bridge circuit may be used as the rectifier.Additionally, the power converter may adapt a reflected impedance of thepower receiver.

The impedance matching circuit (870) may provide impedance matchingbetween a combination of the power converter (860) and the load circuit(840) and the secondary coil. According to an exemplary embodiment, theimpedance matching circuit may generate a resonance of approximately 100kHz, which may reinforce the power transfer. The impedance matchingcircuit (870) may include a capacitor, an inductor, and a switchingdevice that switches the combination of the capacitor and the inductor.The impedance matching may be performed by controlling the switchingdevice of the circuit that configured the impedance matching circuit(870) based on the voltage value, electric current value, power value,frequency value, and so on, of the wireless power that is beingreceived. In some cases, the impedance matching may be carried out eventhough the impedance matching circuit (870) is omitted. Thisspecification also includes an exemplary embodiment of the wirelesspower receiver (200), wherein the impedance matching circuit (870) isomitted.

The coil assembly (880) includes at least one secondary coil, and,optionally, the coil assembly (880) may further include an elementshielding the metallic part of the receiver from the magnetic field.

The communication unit (890) may perform load modulation in order tocommunicate requests and other information to the power transmitter.

For this, the power receiver (830) may perform switching of theresistance or capacitor so as to change the reflected impedance.

The control unit (810) may control the received power. For this, thecontrol unit (810) may determine/calculate a difference between anactual operating point and a target operating point of the powerreceiver (830). Thereafter, by performing a request for adjusting thereflected impedance of the power transmitter and/or for adjusting anoperating point of the power transmitter, the difference between theactual operating point and the target operating point may beadjusted/reduced. In case of minimizing this difference, an optimalpower reception may be performed.

The communication unit (890) and the control unit (810) may each beprovided as a separate device/chipset or may be collectively provided asone device/chipset.

FIG. 9 shows a communication frame structure according to an exemplaryembodiment of the present disclosure. This may correspond to acommunication frame structure in a shared mode.

Referring to FIG. 9, in the shared mode, different forms of frames maybe used along with one another. For example, in the shared mode, aslotted frame having a plurality of slots, as shown in (A), and a freeformat frame that does not have a specified format, as shown in (B), maybe used. More specifically, the slotted frame corresponds to a frame fortransmitting short data packets from the wireless power receiver (200)to the wireless power transmitter (100). And, since the free formatframe is not configured of a plurality of slots, the free format framemay correspond to a frame that is capable of performing transmission oflong data packets.

Meanwhile, the slotted frame and the free format frame may be referredto other diverse terms by anyone skilled in the art. For example, theslotted frame may be alternatively referred to as a channel frame, andthe free format frame may be alternatively referred to as a messageframe.

More specifically, the slotted frame may include a sync patternindicating the starting point (or beginning) of a slot, a measurementslot, nine slots, and additional sync patterns each having the same timeinterval that precedes each of the nine slots.

Herein, the additional sync pattern corresponds to a sync pattern thatis different from the sync pattern that indicates the starting point ofthe above-described frame. More specifically, the additional syncpattern does not indicate the starting point of the frame but mayindicate information related to the neighboring (or adjacent) slots(i.e., two consecutive slots positioned on both sides of the syncpattern).

Among the nine slots, each sync pattern may be positioned between twoconsecutive slots. In this case, the sync pattern may provideinformation related to the two consecutive slots.

Additionally, the nine slots and the sync patterns being provided beforeeach of the nine slots may have the same time interval. For example, thenine slots may have a time interval of 50 ms. And, the nine syncpatterns may have a time length of 50 ms.

Meanwhile, the free format frame, as shown in (B) may not have aspecific format apart from the sync pattern indicating the startingpoint of the frame and the measurement slot. More specifically, the freeformat frame is configured to perform a function that is different fromthat of the slotted frame. For example, the free format frame may beused to perform a function of performing communication of long datapackets (e.g., additional owner information packets) between thewireless power transmitter and the wireless power receiver, or, in caseof a wireless power transmitter being configured of multiple coils, toperform a function of selecting any one of the coils.

Hereinafter, a sync pattern that is included in each frame will bedescribed in more detail with reference to the accompanying drawings.

FIG. 10 is a structure of a sync pattern according to an exemplaryembodiment of the present disclosure.

Referring to FIG. 10, the sync pattern may be configured of a preamble,a start bit, a response field, a type field, an info field, and a paritybit. In FIG. 10, the start bit is illustrated as ZERO.

More specifically, the preamble is configured of consecutive bits, andall of the bits may be set to 0. In other words, the preamble maycorrespond to bits for matching a time length of the sync pattern.

The number of bits configuring the preamble may be subordinate to theoperation frequency so that the length of the sync pattern may be mostapproximate to 50 ms but within a range that does not exceed 50 ms. Forexample, in case the operation frequency corresponds to 100 kHz, thesync pattern may be configured of two preamble bits, and, in case theoperation frequency corresponds to 105 kHz, the sync pattern may beconfigured of three preamble bits.

The start bit may correspond to a bit that follows the preamble, and thestart bit may indicate ZERO. The ZERO may correspond to a bit thatindicates a type of the sync pattern. Herein, the type of sync patternsmay include a frame sync including information that is related to aframe, and a slot sync including information of the slot. Morespecifically, the sync pattern may be positioned between consecutiveframes and may correspond to a frame sync that indicate a start of theframe, or the sync pattern may be positioned between consecutive slotsamong a plurality of slots configuring the frame and may correspond to async slot including information related to the consecutive slots.

For example, in case the ZERO is equal to 0, this may indicate that thecorresponding slot is a slot sync that is positioned in-between slots.And, in case the ZERO is equal to 1, this may indicate that thecorresponding sync pattern is a frame sync being located in-betweenframes.

A parity bit corresponds to a last bit of the sync pattern, and theparity bit may indicate information on a number of bits configuring thedata fields (i.e., the response field, the type field, and the infofield) that are included in the sync pattern. For example, in case thenumber of bits configuring the data fields of the sync patterncorresponds to an even number, the parity bit may be set to when, and,otherwise (i.e., in case the number of bits corresponds to an oddnumber), the parity bit may be set to 0.

The response field may include response information of the wirelesspower transmitter for its communication with the wireless power receiverwithin a slot prior to the sync pattern. For example, in case acommunication between the wireless power transmitter and the wirelesspower receiver is not detected, the response field may have a value of‘00’. Additionally, if a communication error is detected in thecommunication between the wireless power transmitter and the wirelesspower receiver, the response field may have a value of ‘01’. Thecommunication error corresponds to a case where two or more wirelesspower receivers attempt to access one slot, thereby causing collision tooccur between the two or more wireless power receivers.

Additionally, the response field may include information indicatingwhether or not the data packet has been accurately received from thewireless power receiver. More specifically, in case the wireless powertransmitter has denied the data packet, the response field may have avalue of “10” (10—not acknowledge (NAK)). And, in case the wirelesspower transmitter has confirmed the data packet, the response field mayhave a value of “11” (11—acknowledge (ACK)).

The type field may indicate the type of the sync pattern. Morespecifically, in case the sync pattern corresponds to a first syncpattern of the frame (i.e., as the first sync pattern, in case the syncpattern is positioned before the measurement slot), the type field mayhave a value of ‘1’, which indicates a frame sync.

Additionally, in a slotted frame, in case the sync pattern does notcorrespond to the first sync pattern of the frame, the type field mayhave a value of ‘0’, which indicates a slot sync.

Moreover, the information field may determine the meaning of its valuein accordance with the sync pattern type, which is indicated in the typefield. For example, in case the type field is equal to 1 (i.e., in casethe sync pattern type indicates a frame sync), the meaning of theinformation field may indicate the frame type. More specifically, theinformation field may indicate whether the current frame corresponds toa slotted frame or a free-format frame. For example, in case theinformation field is given a value of ‘00’, this indicates that thecurrent frame corresponds to a slotted frame. And, in case theinformation field is given a value of ‘01’, this indicates that thecurrent frame corresponds to a free-format frame.

Conversely, in case the type field is equal to 0 (i.e., in case the syncpattern type indicates a slot sync), the information field may indicatea state of a next slot, which is positioned after the sync pattern. Morespecifically, in case the next slot corresponds to a slot that isallocated (or assigned) to a specific wireless power receiver, theinformation field is given a value of ‘00’. In case the next slotcorresponds to a slot that is locked, so as to be temporarily used bythe specific wireless power receiver, the information field is given avalue of ‘01’. Alternatively, in case the next slot corresponds to aslot that may be freely used by a random wireless power receiver, theinformation field is given a value of ‘10’.

FIG. 11 shows operation statuses of a wireless power transmitter and awireless power receiver in a shared mode according to an exemplaryembodiment of the present disclosure.

Referring to FIG. 11, the wireless power receiver operating in theshared mode may be operated in any one of a selection phase (1100), anintroduction phase (1110), a configuration phase (1120), a negotiationphase (1130), and a power transfer phase (1140).

Firstly, the wireless power transmitter according to the exemplaryembodiment of the present disclosure may transmit a wireless powersignal in order to detect the wireless power receiver. Morespecifically, a process of detecting a wireless power receiver by usingthe wireless power signal may be referred to as an Analog ping.

Meanwhile, the wireless power receiver that has received the wirelesspower signal may enter the selection phase (1100). As described above,the wireless power receiver that has entered the selection phase (1100)may detect the presence or absence of an FSK signal within the wirelesspower signal.

In other words, the wireless power receiver may perform communication byusing any one of an exclusive mode and a shared mode in accordance withthe presence or absence of the FSK signal.

More specifically, in case the FSK signal is included in the wirelesspower signal, the wireless power receiver may operate in the sharedmode, and, otherwise, the wireless power receiver may operate in theexclusive mode.

In case the wireless power receiver operates in the shared mode, thewireless power receiver may enter the introduction phase (1110). In theintroduction phase (1110), the wireless power receiver may transmit acontrol information (CI) packet to the wireless power transmitter inorder to transmit the control information packet during theconfiguration phase, the negotiation phase, and the power transferphase. The control information packet may have a header and informationrelated to control. For example, in the control information packet, theheader may correspond to 0X53.

In the introduction phase (1110), the wireless power receiver performsan attempt to request a free slot for transmitting the controlinformation (CI) packet during the following configuration phase,negotiation phase, and power transfer phase. At this point, the wirelesspower receiver selects a free slot and transmits an initial CI packet.If the wireless power transmitter transmits an ACK as a response to thecorresponding CI packet, the wireless power receiver enters theconfiguration phase. If the wireless power transmitter transmits a NAKas a response to the corresponding CI packet, this indicates thatanother wireless power receiver is performing communication through theconfiguration and negotiation phase. In this case, the wireless powerreceiver re-attempts to perform a request for a free slot.

If the wireless power receiver receives an ACK as a response to the CIpacket, the wireless power receiver may determine the position of aprivate slot within the frame by counting the remaining sync slots up tothe initial frame sync. In all of the subsequent slot-based frames, thewireless power receiver transmits the CI packet through thecorresponding slot.

If the wireless power transmitter authorizes the entry of the wirelesspower receiver to the configuration phase, the wireless powertransmitter provides a locked slot series for the exclusive usage of thewireless power receiver. This may ensure the wireless power receiver toproceed to the configuration phase without any collision.

The wireless power receiver transmits sequences of data packets, such astwo identification data packets (IDHI and IDLO), by using the lockedslots. When this phase is completed, the wireless power receiver entersthe negotiation phase. During the negotiation state, the wireless powertransmitter continues to provide the locked slots for the exclusiveusage of the wireless power receiver. This may ensure the wireless powerreceiver to proceed to the negotiation phase without any collision.

The wireless power receiver transmits one or more negotiation datapackets by using the corresponding locked slot, and the transmittednegotiation data packet(s) may be mixed with the private data packets.Eventually, the corresponding sequence is ended (or completed) alongwith a specific request (SRQ) packet. When the corresponding sequence iscompleted, the wireless power receiver enters the power transfer phase,and the wireless power transmitter stops the provision of the lockedslots.

In the power transfer phase, the wireless power receiver performs thetransmission of a CI packet by using the allocated slots and thenreceives the power. The wireless power receiver may include a regulatorcircuit. The regulator circuit may be included in acommunication/control unit. The wireless power receiver mayself-regulate a reflected impedance of the wireless power receiverthrough the regulator circuit. In other words, the wireless powerreceiver may adjust the impedance that is being reflected for an amountof power that is requested by an external load. This may prevent anexcessive reception of power and overheating.

In the shared mode, (depending upon the operation mode) since thewireless power transmitter may not perform the adjustment of power as aresponse to the received CI packet, in this case, control may be neededin order to prevent an overvoltage state.

A wireless power transmission system may include a message exchangefunction of an application layer for supporting an extension to variousapplication fields. Based on the function, authentication relatedinformation or other information on an application level of a device maybe transmitted and received between a wireless power transmission deviceand a wireless power reception device. For the exchange of higher layermessages between a wireless power transmission device and a wirelesspower reception device, a separate hierarchical architecture for datatransmission is required, and an efficient managing and operating methodis required for the hierarchical architecture.

FIG. 12 shows an application-level data stream between a wireless powertransmitter and a receiver according to an example.

Referring to FIG. 12, a data stream may include an auxiliary datacontrol (ADC) data packet and/or an auxiliary data transport (ADT) datapacket.

The ADC data packet is used to open a data stream. The ADC data packetmay indicate the type of a message included in a stream and the numberof data bytes. Meanwhile, the ADT data packet is sequences of dataincluding an actual message. An ADC/end data packet is used to indicatethe end of the stream. For example, the maximum number of data bytes ina data transport stream may be limited to 2047.

ACK or NACK is used to indicate whether the ADC data packet and the ADTdata packet are normally received. Control information necessary forwireless charging such as a control error packet (CE) or DSR may betransmitted between transmission timings of the ADC data packet and theADT data packet.

Using this data stream structure, authentication related information orother application level information may be transmitted and receivedbetween the wireless power transmitter and the wireless power receiver.

FIG. 13 illustrates a hierarchical architecture for transmitting a datastream between a wireless power transmission device and a wireless powerreception device.

Referring to FIG. 13, a data stream is exchanged between a data streaminitiator and a data stream responder. Both of a wireless powertransmission device and a wireless power reception device may become thedata stream initiator or the data stream responder. For example, in thecase that the data stream initiator is the wireless power receptiondevice, the data stream responder is the wireless power transmissiondevice, and in the case that the data stream initiator is the wirelesspower transmission device, the data stream responder is the wirelesspower reception device.

The data stream initiator generates a message in an application layerlevel (e.g., an authentication related message) and stores it in abuffer managed by an application layer. In addition, the data streaminitiator submits the message stored in the buffer to a transport layerfrom the application layer. The data stream initiator stores the messagein a local buffer managed by the transport layer. A size of the localbuffer of the transport layer may be at least 67 bytes, for example.

The data stream initiator transmits the message to the data streamresponder through a wireless channel by using a data transport stream ofthe transport layer. At this time, the message is transmitted with beingsliced into multiple packets, and this may be called a data transportstream. In the case that an error occurs during the transmission processof data packets, the data stream initiator may retransmit the packet inwhich an error occurs, and in this case, the transport layer of the datastream initiator may perform a feedback for a success or a failure ofthe message transmission for the application layer.

The data stream initiator receives the data transport stream through awireless channel. The received data transport stream is demodulated anddecoded in the reverse process of the process of the data streaminitiator. For example, the data stream responder stores the datatransport stream in the local buffer managed by the transport layer andmerges it, and then forwards it to the application layer. Theapplication layer stores the transferred message in a buffer.

Meanwhile, a size of the local buffer managed by the transport layer maybe different between the data stream initiator and the data streamresponder. That is, a size of the local buffer managed by the transportlayer of the wireless power transmission device may be different from asize of the local buffer managed by the transport layer of the wirelesspower reception device. In addition, a size of the buffer managed by theapplication layer may be different between the data stream initiator andthe data stream responder. That is, a size of the buffer managed by theapplication layer of the wireless power transmission device may bedifferent from a size of the buffer managed by the application layer ofthe wireless power reception device.

In this case, when a size of the exchanged data packet becomes close toa buffer size of either one of the initiator or the responder, data loadis excessively accumulated to any one side of which buffer size issmall, and a problem may occur that a smooth communication isdeteriorated. Accordingly, it is required to adjust a size of datastream to be exchanged properly by considering a buffer size which isdifferent between the initiator and the responder.

Buffer Size Negotiation Method

A buffer size may be defined in various aspects.

In the aspect of layers, a buffer size may mean a size of buffer managedby the application layer or a size of local buffer managed by thetransport layer. Hereinafter, in this embodiment, the term, ‘buffersize’ is used as the concept which is not limited to a layer. That is,in the following embodiments, the term, buffer size may be referred toas a buffer size in the application layer or a buffer size in thetransport layer.

In the aspect of devices, a buffer size may mean a buffer size of thewireless power transmission device or a buffer size of the wirelesspower reception device. Hereinafter, in this embodiment, a buffer sizeof the wireless power transmission device is referred to as PTx buffersize, and a buffer size of the wireless power reception device isreferred to as PRx buffer size.

In order for the wireless power transmission device and the wirelesspower reception device to identify a buffer size therebetween,information for PTx buffer size and information for PRx buffer size maybe used. The information for PTx buffer size may be called a PTx buffersize field, and the information for PRx buffer size may be called a PRxbuffer size field. Alternatively, in relation to ADT, the PTx buffersize and the PRx buffer size may be called an ADT buffer size.

As an example, the PTx buffer size field may be a field included in acapability packet (PTx capability packet) of the wireless powertransmission device (header=0x31). In addition, the PRx buffer size maybe a field included in configuration packet (header=0x51) of thewireless power reception device or a field included in a capabilitypacket (PRx capability packet) of the wireless power reception device.The configuration packet of the wireless power reception device mayinclude not only a basic configuration data of the wireless powerreception device, but also information for additional capabilities.Accordingly, the configuration packet of the wireless power receptiondevice may be identified as the capability packet of the wireless powertransmission device. Hereinafter, a packet including the PRx buffer sizefield is commonly called a configuration packet of the wireless powerreception device.

Alternatively, since the PTx buffer size field and the PRx buffer sizefield are included in different capability packets and distinguishable,the PTx buffer size field and the PRx buffer size field may be simplycalled a buffer size field. In this case, the buffer size field includedin the capability packet of the wireless power transmission deviceindicates the PTx buffer size, and the buffer size field included in thecapability packet of the wireless power reception device indicates thePRx buffer size.

FIG. 14 illustrates a capability packet structure of a wireless powertransmission device including a buffer size field according to anembodiment.

Referring to FIG. 14, a capability packet of a wireless powertransmission device may include, for example, a power class field of 2bits, a guaranteed power value field of 6 bits, a potential power valueof 6 bits, a reserved field, a buffer size field of 2 bits, a WPID(Wireless Power Identifier) field and a Not Res Sens field.

The power class field indicates a power class of the wireless powertransmission device. This field may be set to ‘00’ value (indicatesclass 0).

The guaranteed power value field indicates a maximum guaranteed powervalue included in a power transfer contract (PTC-GP) which is negotiatedby the wireless power transmission device in a current peripheralcondition. Here, for example, the peripheral condition may correspond toa temperature of the wireless power transmission device, a drain poweramount drawable from power sources shared by wireless power transmissiondevices of which power transmitters are different, and/or a presence orabsence of foreign material or friendly metal. The guaranteed powervalue field may indicate a power value in a unit of 0.5 W.

The potential power value indicates a maximum guaranteed power valueincluded in a power transfer contract (PTC-GP) which is negotiated bythe wireless power transmission device in an ideal peripheral condition.Also, this field also indicates a power value in a unit of 0.5 W.

The Not Res Sens field may be configured with different values for eachdesign of an individual wireless power transmission device. Generally,this field may be set to ‘0’ value in order to indicate a wireless powertransmission device design of which frequency is controllable with 150kHz with a power transfer contract including a maximum power value ofgreater than 5 W.

The WPID field indicates that the wireless power transmission device hasa capability of receiving a WPID packet.

The buffer size field indicates a size of buffer for receiving a datatransport stream, for example, 2 bits, and may indicates total 4 typesof buffer sizes. As an example, when a value indicated by the buffersize field is n, the PTx buffer size may be allocated to or defined as2n*k. Here, k represents a minimum buffer size. That is, the buffer sizefield may be represented by a multiplication of the minimum buffer sizeand power of 2.

For example, when k=32×4, in the case that a buffer size field is ‘00’(i.e., code value=0), the PTx buffer size may be 2⁰×32×4=32×4 bytes, andin the case that a buffer size field is ‘01’ (i.e., code value=1), thePTx buffer size may be 2¹×32×4=64×4. And in the case that a buffer sizefield is ‘10’ (i.e., code value=2), the PTx buffer size may be2²×32×4=128×4 bytes, and in the case that a buffer size field is ‘11’(i.e., code value=3), the PTx buffer size may be 2³×32×4=256×4.

The bit number of the buffer size field is just an example, but 3 bitsor more may be allocated thereto. In addition, the information indicatedby each field value is just an example, but the field value indicatingeach information may be changed according to an embodiment.

FIG. 15 illustrates a capability packet structure of a wireless powertransmission device including a buffer size field according to anotherembodiment.

Referring to FIG. 15, a capability packet of a wireless powertransmission device may include, for example, a ‘00’ power class fieldof 2 bits, a negotiable power value of 6 bits, a potential power valueof 6 bits, a reserved field, a duplex (dup) field of 1 bit, anauthentication responder (AR) field of 1 bit, an out band field of 1bit, a buffer size field of 3 bits, a WPID field and a Not Res Sensfield.

The buffer size field indicates a size of buffer for receiving a datatransport stream, for example, 3 bits, and may indicates total 8 typesof buffer sizes. As an example, when a value indicated by the buffersize field is n, the PTx buffer size may be allocated to or defined as2^(n)*k. Here, k represents a minimum buffer size. That is, the buffersize field may be represented by a multiplication of the minimum buffersize and power of 2.

The bit number of the buffer size field is just an example, but 3 bitsor more may be allocated thereto. In addition, the information indicatedby each field value is just an example, but the field value indicatingeach information may be changed according to an embodiment.

FIG. 16 illustrates a configuration packet structure of a wireless powerreception device including a buffer size field according to anembodiment.

Referring to FIG. 16, a configuration packet structure of a wirelesspower reception device may include a ‘00’ field, a reference power fieldof 6 bits, a reserved field, a ZERO field of 1 bit, an authenticationinitiator (AI) field of 1 bit, an out band (OB) field of 1 bit, a ZEROfield of 1 bit, a count field of 3 bits, a window size field of 5 bits,a window offset field of 3 bits, a FSK parameters (Neg field, pol field,and depth field) field, a buffer size field of 3 bits, and a duplex(Dup) field of 1 bit.

The buffer size field indicates a size of buffer for receiving a datatransport stream, for example, 2 bits, and may indicates total 4 typesof buffer sizes. As an example, when a value indicated by the buffersize field is n, the PRx buffer size may be allocated to or defined as2n*k. Here, k represents a minimum buffer size. That is, the buffer sizefield may be represented by a multiplication of the minimum buffer sizeand power of 2.

For example, when k=32×4, in the case that a buffer size field is ‘00’(i.e., code value=0), the PRx buffer size may be 2⁰×32×4=32×4 bytes, andin the case that a buffer size field is ‘01’ (i.e., code value=1), thePRx buffer size may be 2¹×32×4=64×4. And in the case that a buffer sizefield is ‘10’ (i.e., code value=2), the PRx buffer size may be2²×32×4=128×4 bytes, and in the case that a buffer size field is ‘11’(i.e., code value=3), the PRx buffer size may be 2³×32×4=256×4.

The bit number of the buffer size field is just an example, but 3 bitsor more may be allocated thereto. In addition, the information indicatedby each field value is just an example, but the field value indicatingeach information may be changed according to an embodiment.

Hereinafter, it is described in detail a process of identifying a buffersize of a counterpart based on information for PTx buffer size andinformation for PRx buffer size and negotiating a size (or buffer size)of a data transport stream between a wireless power transmission deviceand a wireless power reception device.

The process of negotiating a size (or buffer size) of a data transportstream may be performed in a negotiation phase in a state diagram of awireless power transmission.

FIG. 17 is a flowchart illustrating a method for negotiating a buffersize according to an embodiment. For the convenience of description, inthis embodiment, it is described that the information for PTx buffersize is included in a capability packet of a wireless power transmissiondevice as a PTx buffer size field. In addition, in this embedment, it isdescribed that the information for PRx buffer size is included in aconfiguration packet of a wireless power reception device as a PRxbuffer size field.

Referring to FIG. 17, in an identification and configuration phase, thewireless power reception device transmits a configuration packet to thewireless power transmission device (step, S1700). The configurationpacket includes the PRx buffer size field, and may have the structure ofFIG. 16, for example. The wireless power reception device may inform abuffer size for a data transport stream receivable by the wireless powerreception device itself by using the PRx buffer size field of theconfiguration packet to the wireless power transmission device. Whenreceiving the configuration packet of the wireless power receptiondevice, the wireless power transmission device may identify theinformation for PRx buffer size.

In the case that both of the wireless power transmission device and thewireless power reception device support an extended power profile, thewireless power transmission device and the wireless power receptiondevice may enter the negotiation step.

In the negotiation step, the wireless power reception device transmits arequest packet for requesting a capability packet of the wireless powertransmission device to the wireless power transmission device (step,S1705). At this time, the request packet may be a general request (GRQ)packet or a specific request (SRQ) packet for requesting a buffer sizeonly simply. In this case, the wireless power transmission device andthe wireless power reception device may establish an extended powertransmission contract by using a request packet and/or at least onespecific request packet.

In the case of entering renegotiation step by an attention (ATN) patternof the wireless power transmission device, the wireless power receptiondevice may transmit a DSR packet, instead of the request packet, to thewireless power transmission device. In this case, the wireless powerreception device receives a capability packet from the wireless powertransmission device in response to the DSR.

When receiving the request packet (or DSR), in response thereto, thewireless power transmission device transmits a capability packet (PTxcapability packet) of the wireless power transmission device to thewireless power reception device (step, S1710). At this time, thecapability packet of the wireless power transmission device may includethe information for PTx buffer size, that is, a buffer size field, andmay have a structure as shown in FIG. 14 or FIG. 15, for example.

When receiving the capability packet of the wireless power transmissiondevice, the wireless power reception device may identify the informationfor PTx buffer size from the capability packet of the wireless powertransmission device.

When information for a buffer size is exchanged, the wireless powertransmission device and the wireless power reception device maynegotiate a buffer size (or (ADT) data stream size) to be actually usedas a specific value (step, S1715). In this case, the wireless powertransmission device and the wireless power reception device mayconfigure a data transport stream as a value of the negotiated value asa buffer size or less and transmit it to the counterpart. The negotiatedbuffer size (or (ADT) data stream size) may be an available maximumbuffer size (or maximum ADT data stream size) which is mutuallyavailable to the maximum.

The negotiation step of buffer size may be omitted in some cases. Inthis case, without a separate negotiation of buffer size, either one ofthe wireless power transmission or reception device may configure a datatransport stream based on a buffer size informed by the other. Ofcourse, the operation of adopting and using the buffer size informed bythe other without any change may also be interpreted as the negotiation.

Later, when configuring a data transport stream to send to acounterpart, the wireless power reception device and/or the wirelesspower transmission device may restrict a size (or buffer size) of thedata transport stream based on the buffer size of the counterpart.

That is, when the wireless power reception device configures a datatransport stream to send to the wireless power transmission device, thewireless power reception device may generate, process or control a size(or PTx buffer size) of the data transport stream based on thenegotiated buffer size (or PTx buffer size) (step, S1720). Later, thewireless power reception device transmits the data transport stream tothe wireless power transmission device (step, S1725).

Meanwhile, when the wireless power transmission device configures a datatransport stream to send to the wireless power reception device, thewireless power transmission device may generate, process or control asize (or PRx buffer size) of the data transport stream based on thenegotiated buffer size (or PRx buffer size) (step, S1730). Later, thewireless power transmission device transmits the data transport streamto the wireless power reception device (step, S1735).

The wireless power transmission device according to the embodiment ofFIG. 17 as such corresponds to the wireless power transmission device,the wireless power transmitter or a power transmitter described in FIG.1 to FIG. 11. Accordingly, the operation of the wireless powertransmission device of the present embodiment is implemented by one orthe combination of two or more elements of the wireless powertransmission device in FIG. 1 to FIG. 11. For example, in thisembodiment, the operation of transmitting wireless power may beperformed by a power conversion unit 110. Furthermore, in thisembodiment, an operation of receiving a configuration packet and arequest packet, an operation of generating and transmitting a PTxcapability packet, an operation of negotiating a buffer size and anoperation of generating and transmitting a data transport stream basedon a PRx buffer size may be performed by a communication/control unit120.

In addition, the wireless power reception device according to theembodiment of FIG. 17 corresponds to the wireless power receptiondevice, the wireless power receiver or a power receiver described inFIG. 1 to FIG. 11. Accordingly, the operation of the wireless powerreception device of the present embodiment is implemented by one or thecombination of two or more elements of the wireless power receptiondevice in FIG. 1 to FIG. 11. For example, in this embodiment, theoperation of receiving wireless power may be performed by a power pickupunit 210. Furthermore, in this embodiment, an operation of generatingand transmitting a configuration packet and a request packet, anoperation of receiving a PTx capability packet, an operation ofnegotiating a buffer size and an operation of generating andtransmitting a data transport stream based on a PTx buffer size may beperformed by a communication/control unit 220.

Hereinafter, it is described other operation for improving a function oftransport layer.

Symmetric Communication Method

ASK scheme is used for a communication from a wireless power receptiondevice to a wireless power transmission device, and FSK scheme is usedfor a communication from a wireless power transmission device to awireless power reception device. The communication schemes therebetweenare different, but it is preferable to be configured to have a symmetricor the same structure for those having the same content or function asinformation carried by ASK or FSK.

For example, it is preferable that a response of the wireless powertransmission device in response to a packet transmitted by the wirelesspower reception device and a response of the wireless power receptiondevice in response to a packet transmitted by the wireless powertransmission device have a symmetric structure with each other.

In response to the packet transmitted by the wireless power receptiondevice, the wireless power transmission device generates and transmitsFSK bit pattern. FSK bit pattern includes ACK/NAK/ND/ATN.

Meanwhile, in response to the packet transmitted by the wireless powertransmission device, the wireless power reception device generates andtransmits a response packet. In order to have a symmetric structure, theresponse packet of the wireless power reception device may be configuredto have the structure shown in FIG. 18, for example.

FIG. 18 illustrates a structure of a response packet of a wireless powerreception device according to an example.

Referring to FIG. 18, a header value of ASK response packet is 0x15, andthe payload is 8 bits and may indicate the following values.

0xFF: ACK

0x00: NAK

0x55: ND

0x33: ATN

The information indicated by ASK response packet and the correspondingvalue are just an example, but the value indicating each information maybe changed according to an embodiment.

Definition of Poll Packet

In addition to ASK response packet, a poll packet may be defined. Thepoll packet is a packet used for a response to ATN bit pattern responseof a wireless power transmission device. The poll packet is used forinquiring a reason of ATN bit pattern. The poll packet is DSR packet,and in the case that a transmission use or purpose of DSR packet isindicated as ‘poll’, this may be called a poll packet.

When a wireless power reception device transmits a poll packet to awireless power transmission device, the wireless power transmissiondevice reports a reason of ATN bit pattern to the wireless powerreception device.

As an example, the operation of reporting to the wireless powerreception device may include an operation that the wireless powertransmission device transmits a capability packet (header value=0x31) ofthe wireless power transmission device to the wireless power receptiondevice. This operation is performed when the wireless power transmissiondevice wants a power renegotiation by the wireless power transmissiondevice (PTx-initiated power renegotiation).

As another example, the operation of reporting to the wireless powerreception device may include an operation that the wireless powertransmission device transmits ADC data packet (header value=0x25) to thewireless power reception device. This operation is performed when thewireless power transmission device is going to initiate a data transportstream of a higher layer (i.e., ADT data stream).

Processing Method of Missing ADT Data Packet

After a wireless power transmission device or a wireless power receptiondevice receives a packet, ACK/NACK transmitted in response thereto maybe corrupted when a communication environment is deteriorated. In thiscase, missing of ADT packet may occur. The present disclosure includes amethod for solving it.

FIG. 19 illustrates a method for processing ADT data packet according toan example.

Referring to FIG. 19, it is assumed the case that a wireless powertransmission device transmits an ADT packet 1900, and a wireless powerreception device responds with an ACK 1905, but the ACK 1905 iscorrupted. In this case, the ADT packet is no more transmitted (1910),and thereafter, the wireless power reception device transmits an ATNpacket 1910 to the wireless power transmission device and induces toretransmit a previous ADT packet.

Interpretation Method of ATN Bit Pattern

According to the present embodiment, an interpretation of ATN bitpattern or ATN packet may be changed depending on whether ATN bitpattern or ATN packet transmitted by a wireless power transmissiondevice or a wireless power reception device is a response to a certainprecedent packet.

As an example, in the case that ATN bit pattern or ATN packet is aresponse to a reception power packet, ATN bit pattern may be interpretedas an attention for requesting a communication to a counterpart.

As another example, in the case that ATN bit pattern is a response toATN data packet, since a reception side fails to receive just previousADT packet properly, ATN bit pattern may be interpreted as a request ofretransmitting the just previous ADT packet again to a transmitter side.

Since the wireless power transmitting method and apparatus or thewireless power receiver and method according to an embodiment of thepresent disclosure do not necessarily include all the elements oroperations, the wireless power transmitter and method and the wirelesspower transmitter and method may be performed with the above-mentionedcomponents or some or all of the operations. Also, embodiments of theabove-described wireless power transmitter and method, or receivingapparatus and method may be performed in combination with each other.Also, each element or operation described above is necessarily performedin the order as described, and an operation described later may beperformed prior to an operation described earlier.

The description above is merely illustrating the technical spirit of thepresent disclosure, and various changes and modifications may be made bythose skilled in the art without departing from the essentialcharacteristics of the present disclosure. Therefore, the embodiments ofthe present disclosure described above may be implemented separately orin combination with each other.

Therefore, the embodiments disclosed in the present disclosure areintended to illustrate rather than limit the scope of the presentdisclosure, and the scope of the technical spirit of the presentdisclosure is not limited by these embodiments. The scope of the presentdisclosure should be construed by claims below, and all technicalspirits within a range equivalent to claims should be construed as beingincluded in the right scope of the present disclosure.

1. A wireless power receiver device, comprising: a power pickup circuitconfigured to receive a wireless power generated based on magneticcoupling from a wireless power transmitter device in a power transferphase; and a communication/control circuit configured to receive, fromthe wireless power transmitter device, information for a first buffersize, wherein the information for the first buffer size informs a sizeof a first buffer for the wireless power transmitter device to receive adata transfer stream, wherein the first buffer size is defined as amultiplication of a minimum buffer size k and 2n, and wherein theinformation for the first buffer size is related with the n.
 2. Thewireless power receiver device of claim 1, wherein the information forthe first buffer size is received by being included in a capabilitypacket of the wireless power transmitter device.
 3. The wireless powerreceiver device of claim 1, wherein the information for the first buffersize is received in a negotiation phase.
 4. The wireless power receiverdevice of claim 1, wherein the communication/control circuit is furtherconfigured to transmit, to the wireless power transmitter device,information for a second buffer size, wherein the information for thesecond buffer size informs a size of a second buffer for the wirelesspower transmitter device to receive a second data transfer stream. 5.The wireless power receiver device of claim 4, wherein the informationfor the second buffer size is transmitted with being included in aconfiguration packet of the wireless power receiver device.
 6. Thewireless power receiver device of claim 4, wherein the second buffersize is defined as a multiplication of a second minimum buffer size k′and 2m, and wherein the information for the second buffer size isrelated with the m.
 7. A wireless power transmitter device, comprising:a power conversion circuit configured to transmit a wireless powergenerated based on magnetic coupling to a wireless power receiver devicein a power transfer phase; and a communication/control circuitconfigured to transmit, to the wireless power receiver device,information for a first buffer size, wherein the information for thefirst buffer size informs a size of a first buffer for the wirelesspower transmitter device to receive a data transfer stream, wherein thefirst buffer size is defined as a multiplication of a minimum buffersize k and 2n, and wherein the information for the first buffer size isrelated with the n.
 8. The wireless power transmitter device of claim 7,wherein the information for the first buffer size is transmitted bybeing included in a capability packet of the wireless power transmitterdevice.
 9. The wireless power transmitter device of claim 7, wherein theinformation for the first buffer size is transmitted in a negotiationphase.
 10. The wireless power transmitter device of claim 7, wherein thecommunication/control circuit is further configured to receive, from thewireless power receiver device, information for a second buffer size,wherein the information for the second buffer size informs a size of asecond buffer for the wireless power receiver device to receive a seconddata transfer stream.
 11. The wireless power transmitter device of claim10, wherein the information for the second buffer size is received withbeing included in a configuration packet of the wireless power receiverdevice.
 12. The wireless power transmitter device of claim 10, whereinthe second buffer size is defined as a multiplication of a secondminimum buffer size k′ and 2m, and wherein the information for thesecond buffer size is related with the m.
 13. A method performed by awireless power receiver device, the method comprising: receiving awireless power generated based on magnetic coupling from a wirelesspower transmitter device in a power transfer phase; and receiving, fromthe wireless power receiver device, information for a first buffer size,wherein the information for the first buffer size informs a size of afirst buffer for the wireless power transmitter device to receive a datatransfer stream, wherein the first buffer size is defined as amultiplication of a minimum buffer size k and 2n, and wherein theinformation for the first buffer size is related with the n.
 14. Themethod of claim 13, wherein the information for the first buffer size isreceived by being included in a capability packet of the wireless powertransmitter device.
 15. The method of claim 13, wherein the informationfor the first buffer size is received in a negotiation phase.
 16. Themethod of claim 13, further comprising: transmitting, to the wirelesspower transmitter device, information for a second buffer size, whereinthe information for the second buffer size informs a size of a secondbuffer for the wireless power transmitter device to receive a seconddata transfer stream.
 17. The method of claim 16, wherein theinformation for the second buffer size is transmitted with beingincluded in a configuration packet of the wireless power receiverdevice.
 18. The method of claim 16, wherein the second buffer size isdefined as a multiplication of a second minimum buffer size k′ and 2m,and wherein the information for the second buffer size is related withthe m.